On Friday seven people were confirmed as having MERS, followed by 18 more on Saturday, the biggest daily increase in new infections so far. The total number of cases in the kingdom is 396, of whom 109 have died.

The new cases include nine in Riyadh, 10 in Jeddah, four in Mecca and two in Medina. In July many foreign pilgrims are expected to visit Mecca and Medina during Islam's fasting month of Ramadan. Millions more are expected in early October for the annual Haj.

On Friday the United States said it had discovered its first confirmed case of the disease in a man who had recently been in Saudi Arabia. Egypt said it discovered its first case, also in a man who had been in Saudi Arabia, on Thursday.

Infections of MERS in Saudi Arabia, where it was discovered two years ago, have more than doubled since the start of April, but the total number of deaths has increased at a slower rate.