The Defence Ministry said the sapper units were airlifted to Syria with equipment including state-of-the art robotic devices to defuse mines at the 2,000-year-old archaeological site. Russian television stations showed Il-76 transport planes with the engineers landing before dawn at the Russian air base in Syria.

Sunday's recapture of Palmyra by Syrian troops under the cover of Russian airstrikes was an important victory over Islamic State militants who operated a 10-month reign of terror there.

Lt. Gen. Sergei Rudskoi of the military's General Staff said Russian military advisers had helped plan and direct the Syrian army's operation to recapture Palmyra.

He said Russian warplanes had flown about 500 combat missions from March 7 to March 27, striking 2,000 targets around Palmyra, including artillery positions and fortifications. The Russian jets also hit IS militants as they tried to flee toward their strongholds of Raqqa and Deir el-Zour, Rudskoi added.

The high number of sorties flown in support of the offensive on Palmyra demonstrated Russia's ability to provide strong backing to Syrian President Bashar Assad's military despite a partial pullout of Russian combat jets from Syria earlier this month. Russian President Vladimir Putin has said the drawdown should help the Syria peace talks that began in Geneva, but he has vowed to continue fighting IS and the al-Qaida-linked Nusra Front. A Russian- and U.S.-brokered cease-fire in Syria that began on February 27 has largely held, but the Islamic State group and the Nusra Front have been excluded from it. Rudskoi said the truce helped the Syrian military intensify its operations against those two rebel groups. While some Russian warplanes were sent back home after a heavy-duty service in the air campaign that began on Sept. 30, the Russian military have deployed new weapons at the Hemeimeem air base in Syria's coastal province of Latakia, the heartland of Assad's Alawite minority.

- DAILY MAIL