Drone attacks have set alight two major oil facilities run by the state-owned company Aramco in Saudi Arabia, state media say. Footage showed a huge blaze at Abqaiq, site of Aramco's largest oil processing plant, while a second drone attack started fires in the Khurais oilfield. The fires are now under control at both facilities, state media said.A spokesman for the Iran-aligned Houthi group in Yemen said it had deployed 10 drones in the attacks.The military spokesman, Yahya Sarea, told al-Masirah TV, which is owned by the Houthi movement and is based in Beirut, that further attacks could be expected in the future.He said Saturday's attack was one of the biggest operations the Houthi forces had undertaken inside Saudi Arabia and was carried out in "co-operation with the honourable people inside the kingdom".Saudi officials have not yet commented on who they think is behind the attacks."At 04:00 (01:00 GMT), the industrial security teams of Aramco started dealing with fires at two of its facilities in Abqaiq and Khurais as a result of... drones," the official Saudi Press Agency reported."The two fires have been controlled."Abqaiq is about 60km (37 miles) south-west of Dhahran in Saudi Arabia's Eastern Province, while Khurais, some 200km further south-west, has the country's second largest oilfield.

What are the facilities? The Abqaiq plant turns sour crude into sweet crude, producing up to 7 million barrels a day. Aramco says it is the world's largest "crude oil stabilisation plant". Saudi security forces foiled an attempt by al-Qaeda to attack the Abqaiq facility with suicide bombers in 2006. The Khurais oilfield came on line in 2009 and is the nation's second-largest after Ghawar. Khurais reportedly produces 1.5 million barrels a day with estimated recoverable oil reserves of more than 20 billion barrels.Global oil markets are closed for the weekend so there was no immediate effect on prices. A Saudi state media correspondent said that "oil exports are ongoing" following the attacks, but gave no further details.The attacks come as Aramco prepares for a much-anticipated initial public offering (IPO), part of a reform package led by King Salman's son, Crown Prince Mohammed bin Salman, to reduce the economy's reliance on oil.Who carried out the attacks? The Iran-aligned Houthi rebel movement has been fighting the Yemeni government and a Saudi-led coalition.

Yemen has been at war since 2015, when President Abdrabbuh Mansour Hadi was forced to flee the capital Sanaa by the Houthis. Saudi Arabia backs President Hadi, and has led a coalition of regional countries against the rebels. Mr Sarea, the Houthi group's military spokesman, told al-Masirah that operations against Saudi targets would "only grow wider and will be more painful than before, so long as their aggression and blockade continues".Houthi fighters were blamed for drone attacks on the Shaybah natural gas liquefaction facility last month and on other oil facilities in May.There have been other sources of tension in the region, often stemming from the rivalry between Saudi Arabia and Iran.Saudi Arabia and the US both blamed Iran for attacks in the Gulf on two oil tankers in June and July, allegations Tehran denied.

In May, four tankers, two of them Saudi-flagged, were damaged by explosions within the UAE's territorial waters in the Gulf of Oman. Saudi Arabia and then US National Security Adviser John Bolton blamed Iran. Tehran said the accusations were "ridiculous”. Tension in the vital shipping lanes worsened when Iran shot down a US surveillance drone over the Strait of Hormuz in June, leading a month later to the Pentagon announcing the deployment of US troops to Saudi Arabia.

For a little more than three years, Yemen has been locked in a seemingly intractable civil war that has killed nearly 10,000 people and pushed millions to the brink of starvation.The conflict has its roots in the Arab Spring of 2011, when an uprising forced the country's long-time authoritarian president, Ali Abdullah Saleh, to hand over power to his deputy, Abdrabbuh Mansour Hadi. The political transition was supposed to bring stability to Yemen, one of the Middle East's poorest nations, but President Hadi struggled to deal with various problems including militant attacks, corruption, food insecurity, and continuing loyalty of many military officers to Saleh.

Fighting began in 2014 when the Houthi Shia Muslim rebel movement took advantage of the new president's weakness and seized control of northern Saada province and neighbouring areas. The Houthis went on to take the capital Sanaa, forcing Mr Hadi into exile abroad.The conflict escalated dramatically in March 2015, when Saudi Arabia and eight other mostly Sunni Arab states - backed by the US, UK, and France - began air strikes against the Houthis, with the declared aim of restoring Mr Hadi's government.The Saudi-led coalition feared that continued success of the Houthis would give their rival regional power and Shia-majority state, Iran, a foothold in Yemen, Saudi Arabia's southern neighbour. Saudi Arabia says Iran is backing the Houthis with weapons and logistical support - a charge Iran denies.Both sides have since been beset by infighting. The Houthis broke with Saleh and he was killed by Houthi fighters in December 2017. On the anti-Houthi side, militias include separatists seeking independence for south Yemen and factions who oppose the idea.

The stalemate has produced an unrelenting humanitarian crisis, with at least 8.4 million people at risk of starvation and 22.2 million people - 75% of the population - in need of humanitarian assistance, according to the UN. Severe acute malnutrition is threatening the lives of almost 400,000 children under the age of five. Yemen’s health system has all but collapsed, while the world's largest cholera outbreak has killed thousands. In June 2018, Saudi-backed government forces began an assault on the key rebel-held port of Hudaydah, the entry point for the vast majority of aid going into Yemen and a lifeline for the starving. Aid agencies warned the offensive could make Yemen's humanitarian catastrophe much worse.

More than 60% of civilian deaths have been the result of Saudi-led air strikes, the UN says Yemen, one of the Arab world's poorest countries, has been devastated by a civil war. Here we explain what is fuelling the fighting, and who is involved.

The conflict has its roots in the failure of a political transition supposed to bring stability to Yemen following an Arab Spring uprising that forced its longtime authoritarian president, Ali Abdullah Saleh, to hand over power to his deputy, Abdrabbuh Mansour Hadi, in 2011.As president, Mr Hadi struggled to deal with a variety of problems, including attacks by jihadists, a separatist movement in the south, the continuing loyalty of security personnel to Saleh, as well as corruption, unemployment and food insecurity. The Houthi movement, which champions Yemen's Zaidi Shia Muslim minority and fought a series of rebellions against Saleh during the previous decade, took advantage of the new president's weakness by taking control of their northern heartland of Saada province and neighbouring areas.Disillusioned with the transition, many ordinary Yemenis - including Sunnis - supported the Houthis and in late 2014 and early 2015, the rebels took over Sanaa.

The Houthis and security forces loyal to Saleh - who is thought to have backed his erstwhile enemies in a bid to regain power - then attempted to take control of the entire country, forcing Mr Hadi to flee abroad in March 2015.Alarmed by the rise of a group they believed to be backed militarily by regional Shia power Iran, Saudi Arabia and eight other mostly Sunni Arab states began an air campaign aimed at restoring Mr Hadi's government.The coalition received logistical and intelligence support from the US, UK and France.

At the start of the war Saudi officials forecast that the war would last only a few weeks. But four years of military stalemate have followed.Coalition ground troops landed in the southern port city of Aden in August 2015 and helped drive the Houthis and their allies out of much of the south over the next few months. Mr Hadi's government has established a temporary home in Aden, but it struggles to provide basic services and security and the president remains in exile.

The Houthis meanwhile have not been dislodged from Sanaa, and have been able to maintain a siege of the third city of Taiz and to fire ballistic missiles across the border with Saudi Arabia.Militants from al-Qaeda in the Arabian Peninsula (AQAP) and the local affiliate of the rival Islamic State group (IS) have taken advantage of the chaos by seizing territory in the south and carrying out deadly attacks, notably in Aden.

The launch of a ballistic missile towards Riyadh in November 2017 prompted the Saudi-led coalition to tighten its blockade of Yemen.The coalition said it wanted to halt the smuggling of weapons to the rebels by Iran - an accusation Tehran denied - but the restrictions led to substantial increases in the prices of food and fuel, helping to push more people into food insecurity.In June 2018, the coalition attempted to break the deadlock on the battlefield by launching a major offensive on the rebel-held Red Sea city of Hudaydah, whose port is the principal lifeline for almost two thirds of Yemen's population.

UN officials warned that the toll in lives might be catastrophic if the port was damaged or blocked. But months passed before the warring parties could be persuaded to attend talks in Sweden to avert an all-out battle in Hudaydah.In December, government and Houthi representatives agreed to a ceasefire in Hudaydah city and port and promised to redeploy their forces by mid-January. But both sides have yet to start withdrawing, raising fears that the deal will collapse.In short, Yemen is experiencing the world's worst man-made humanitarian disaster.

The UN says at least 7,025 civilians have been killed and 11,140 injured in the fighting since March 2015, with 65% of the deaths attributed to Saudi-led coalition air strikes.An international group tracking the civil war believes the death toll is far higher. The US-based Armed Conflict Location & Event Data Project estimates that more than 67,650 civilians and combatants have been killed since January 2016, based on news reports of each incident of violence.Thousands more civilians have died from preventable causes, including malnutrition, disease and poor health.About 80% of the population - 24 million people - need humanitarian assistance and protection.About 20 million need help securing food, including almost 10 million who the UN says are just a step away from famine. Almost 240,000 of those people are facing "catastrophic levels of hunger".More than 3 million people - including 2 million children - are acutely malnourished, which makes them more vulnerable to disease. The charity Save the Children estimates that 85,000 children with severe acute malnutrition may have died between April 2015 and October 2018.With only half of the country's 3,500 medical facilities fully functioning, almost 20 million people lack access to adequate healthcare. And almost 18 million do not have enough clean water or access to adequate sanitation.Consequently, medics have struggled to deal with the largest cholera outbreak ever recorded, which has resulted in more than 1.49 million suspected cases and 2,960 related deaths since April 2017.The war has also displaced more than 3.3 million from their homes, including 685,000 who have fled fighting along the west coast since June 2018.

Ali Abdullah Saleh died amid fierce clashes between his supporters and the Houthis in SanaaThe alliance between the Houthis and Mr Saleh collapsed in November 2017 following clashes over control of Sanaa's biggest mosque that left dozens of people dead.Houthi fighters launched an operation to take full control of the capital and on 4 December 2017 announced that Mr Saleh had been killed.Only weeks later, infighting among pro-government forces erupted.Separatists seeking independence for south Yemen, which was a separate country before unification with the north in 1990, formed an uneasy alliance with troops loyal to Mr Hadi in 2015 to stop the Houthis capturing Aden.

But in January 2018 the separatist movement known as the Southern Transitional Council (STC) accused the Hadi government of corruption and mismanagement, and demanded the removal of the prime minister.Southern separatists fought Hadi loyalists after their demand for a cabinet reshuffle was rejectedClashes erupted when separatist units attempted to seize government facilities and military bases in Aden by force.The situation was made more complex by divisions within the Saudi-led coalition. Saudi Arabia reportedly backs Mr Hadi, who is based in Riyadh, while the United Arab Emirates is closely aligned with the separatists.Calm was restored in Aden after a few weeks, but tensions between the two groups remain. In September, there were protests after separatist officials called for a peaceful popular uprising in the South.

Suicide bombings claimed by the Islamic State group have killed dozens of people in AdenWhat happens in Yemen can greatly exacerbate regional tensions. It also worries the West because of the threat of attacks - such as from al-Qaeda or IS affiliates - emanating from the country as it becomes more unstable.The conflict is also seen as part of a regional power struggle between Shia-ruled Iran and Sunni-ruled Saudi Arabia.Gulf Arab states - backers of President Hadi - have accused Iran of bolstering the Houthis financially and militarily, though Iran has denied this.Yemen is also strategically important because it sits on a strait linking the Red Sea with the Gulf of Aden, through which much of the world's oil shipments pass

Yemen war: Has anything been achieved?

By Frank Gardner

This summer's partial withdrawal of Emirati forces from Yemen, while the war still drags on, prompts the inevitable question - has anything been achieved by anyone in this conflict? Even the United Arab Emirates (UAE) - Saudi Arabia's closest ally - pronounced on 22 July: "There was no easy victory and there will be no easy peace. “Let’s start with the downside. What has been lost and the scale of the disaster here is quite staggering. The Yemen war, now in its fifth year, has rightly been branded the worst humanitarian crisis of our time. Estimates of those killed range from 10,000 to more than 70,000, the vast majority being Yemenis and an estimated two-thirds of those deaths from Saudi-led air strikes.According to the UN's Under-Secretary General for Humanitarian Affairs, Mark Lowcock, there are more than 30 front lines; more than 3.3 million people have been displaced; and 80% of the population need assistance and protection, including 10 million now reliant on food aid.Transpose those figures on to a UK population and it would notionally mean 53 million people needing help and protection.So Yemen, already the Arab world's poorest country, has been plunged ever deeper into poverty and economic disaster.

This year, the Yemen war is already spreading beyond its borders, with missile and drone attacks by Houthi rebels on Saudi border towns, on shipping in the Red Sea and reportedly even on targets as far away as Riyadh and the UAE.Yet for Yemen's legitimate, UN-recognised government and its Saudi and Emirati backers, this war has always been about preventing an unacceptable takeover of the country by a tiny minority with links to Iran - the Houthis. And in that, they have succeeded, albeit at a terrible price paid by the people of Yemen.

Saudi-led air strikes have caused huge loss of life and widespread destruction The war did not begin with the Saudi-led air campaign in March 2015. It began six months earlier when the Houthis, a small, largely unheard-of Yemeni tribal group from the mountainous north, marched on the capital, Sanaa, and evicted the legitimate government. Then, with the backing of forces loyal to the ousted former Yemeni President Ali Abdallah Saleh, the Houthis took over most of the populated areas of Yemen.

For Saudi Arabia, Iran's regional rival, this felt like an Iranian-backed coup on its southern frontier and the ruling princes resolved to act. Propelled by its inexperienced defence minister and now Crown Prince, Mohammed bin Salman, Saudi Arabia put together a hastily-assembled coalition and began a devastating campaign of air strikes on Houthi positions. When I visited its operations centre in Riyadh in April 2015, the coalition spokesman was confident that within a few months Houthi resistance would crumble and they would effectively sue for peace. Yet more than four years on, the air strikes continue. There have been peace talks, but no peace.So has the war achieved nothing? That is certainly how it looks to much of the rest of the world.

And the British government has found itself dragged into court, accused by human rights activists of providing weapons and munitions to the Royal Saudi Air Force which has, on several occasions over the past four years, bombed schools, hospitals, market places and funerals, killing civilians.The Houthis, too, have committed alleged war crimes but Britain isn't supplying them.The UAE, which at one point had up to 7,000 troops deployed in Yemen, has now reduced its contingent there to a few hundred, leaving the Saudis and their Yemeni allies to fight the Houthis, who remain firmly embedded in and around the capital and the north of the country.The UAE view is that its participation in this war has helped achieve several things. It has prevented a Houthi takeover of the whole country, which it considers would have ultimately given Iran control over the strategic Bab al-Mandeb Strait between Africa and Arabia. Also, it has "liberated" most of Yemen and undermined the al-Qaeda in the Arabian Peninsula group.

For Saudi Arabia, though, which has sunk billions of riyals into this war, and which now finds its towns and airports regularly targeted by increasingly sophisticated Houthi drones, the gains are less clear.Michael Stephens, a Gulf expert with the Royal United Services Institute (Rusi) think-tank in London, believes the war has been damaging for the Saudis as well as for Yemen."The war has produced little of benefit for Saudi Arabia and strategically you could say that Riyadh is in a weaker position than it was in 2015," he said."In contrast, the UAE has been able to achieve a number of tactical and political goals which have reinforced its position as a growing regional power."Meanwhile, the much-heralded Stockholm peace talks of last December have failed to translate into a lasting peace deal - or even a lasting ceasefire. While others can debate what they have gained or lost in Yemen, that country's agony continue