Air raids reportedly kill hundreds of fighters and force withdrawal of group hours after it re-entered the ancient city.

The Syrian army, aided by Russian aerial onslaught, has forced ISIL fighters to withdraw from Syria’s Palmyra at dawn on Sunday, only hours after the armed group had re-entered the ancient city.

Both the Russian Defence Ministry and a UK-based monitoring group reported early on Sunday that the Syrian forces, with the support of intense Russian air raids, killed a large number of fighters in the strategically located central city.

According to the Russian ministry, Russian jets carried out 64 strikes during the operation, killing more than 300 fighters.

The Syrian Observatory for Human Rights was unable to confirm the number of those killed.

“The [Syrian] army brought reinforcements into Palmyra last night, and the raids are continuing on [ISIL] positions around the city,” Rami Abdulrahman, director of the Observatory, told AFP news agency.

Amaq news agency affiliated to the armed group however, said they have captured Palmyra castle overlooking the ancient city.

ISIL began an offensive just days ago near Palmyra, an ancient city on UNESCO’s World Heritage list.

In May last year, the armed group seized several towns in Homs province including Palmyra, where they caused extensive damage to many of its ancient sites.

They were forced out of Palmyra in March by Syrian government forces backed by Russia.