French and Russian air strikes in northern Syria have killed at least 33 terrorists of the so-called ’Islamic State of Iraq and the Levant’ (ISIL) takfiri group in the last 72 hours.

French and Russian air strikes in northern Syria have killed at least 33 terrorists of the so-called 'Islamic State of Iraq and the Levant' (ISIL) takfiri group in the last 72 hours, a monitoring group said on Wednesday.

Dozens of ISIL operatives were also wounded in the raids on weapons depots, barracks and checkpoints in the terroriststs' stronghold of Raqqa, said Rami Abdul Rahman, director of the Britain-based opposition Syrian Observatory for Human Rights.

France intensified strikes on Raqqa following last week's attacks in Paris that left 129 dead, with warplanes carrying out dozens of raids on Sunday, Monday and Tuesday.

Russia also pounded Raqqa with long-range bombers and sea-launched missiles on Tuesday, after Moscow confirmed that a bomb attack brought down a Russian passenger jet over Egypt last month, killing all 224 people on board.

"There were only guards around the depots and barracks and most of those killed were at the checkpoints," said Abdul Rahman.

He added many families of foreign armed mercenaries had also left the city for Mosul in Iraq, another stronghold of ISIL takfiri group.