Thirty three IS militants killed in French, Russian raids

French and Russian air strikes in northern Syria have killed at least 33 Islamic State group militants in the last 72 hours, a monitoring group said on Wednesday.

Dozens of IS fighters were also wounded in the raids on weapons depots, barracks and checkpoints in the group's de facto Syrian capital of Raqqa, said Rami Abdel Rahman, director of the Britain-based 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.

"The limited number of deaths can be explained by the fact that the jihadists had taken precautions," said Abdel Rahman, who relies on a network of activists, medics and other sources inside Syria.

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

He said many families of foreign fighters had also left the city for Mosul in Iraq, another stronghold of IS, which has seized control of large parts of Syria and Iraq.

Part of the enhanced French efforts is the entrance of the aircraft carrier Charles de Gaulle to the coalition armada, which will be operational in the eastern Mediterranean "by the end of the week", Defence Minister Jean-Yves Le Drian told parliament on Wednesday.

The Charles de Gaulle left the southern port of Toulon earlier on Wednesday to take part in intensified air strikes against Islamic State targets.

With 26 fighter jets aboard - 18 Rafale and eight Super Etendard - France will have a total 44 aircraft in the area, including 12 based in the United Arab Emirates and six in Jordan.