Coalition jets pound IS 'capital' in Syria, oil trucks

US-led coalition warplanes have pounded the Islamic State group in Syria after the Paris attacks, with French raids hitting IS stronghold Raqa and another strike destroying dozens of oil tankers.

In its first major military response to Friday's attacks in Paris, France said 12 of its warplanes had hit IS positions in Raqa, the jihadists' de facto Syrian capital.

In Paris, President Francois Hollande said France would "intensify" operations in Syria.

"We will continue the strikes in the weeks to come," he told an exceptional meeting of both houses of parliament.

Activists and a monitoring group said the wave of strikes had shaken Raqa and sparked panic, but the number of casualties was not yet known.

"There were at least 36 explosions overnight in Raqa city, some caused by air strikes and some by weapons and explosives detonating after being hit," said Rami Abdel Rahman, director of the Syrian Observatory for Human Rights.

"The blasts shook the entire city," he told AFP.

France's defence ministry said warplanes, including Rafale and Mirage fighters, had dropped 20 bombs on targets including a command post, a recruitment centre and arms depots south of Raqa.

A training camp west of the city was also hit, it said.

The strikes came after IS claimed responsibility for the bomb and gun attacks that killed at least 129 people in Paris.

"IS has imposed a security alert on the city, and it is difficult to confirm information about casualties from hospitals there," Abdel Rahman said.

He said IS had already imposed security measures in Raqa after previous raids, including evacuating some headquarters and moving the families of foreign fighters elsewhere.