(VOVworld) – The Islamic State has expelled Syrian government forces from the northern province of al-Raqqa in a lightning counter-offensive, the Syrian Observatory for Human Rights reported on Monday.

Soldiers from the Syrian army carry a rocket to fire at Islamic State group positions in the province of al-Raqqa, Syria. (Photo: AP)

The attack, which was launched late on Sunday to lead a regime offensive into the IS stronghold of al-Raqqa, advanced around 20 kilometers toward the town of al-Tabqa. More than 40 members of the pro-regime forces were killed while IS casualties were unknown.

In early June, Syrian troops, backed by Russian air strikes, pushed into al-Raqqa, aiming for Syria’s largest dam at Tabqa on the Euphrates River and an air base which have both been under IS control since 2014.