France launched "massive" air strikes against DAESH in Syria Sunday night, destroying a training camp and a munitions dump in the city of Raqqa, where Iraqi intelligence officials say the attacks on Paris were planned.

12 aircraft including 10 fighter jets dropped a total of 20 bombs in the biggest air strikes since France extended its bombing campaign against the extremist group in Syria in September, a French Defense Ministry statement said. The jets launched from sites in Jordan and the Persian Gulf, in coordination with U.S. forces.

On the sidelines of the G20 summit in Turkey on Sunday, France's Foreign Minister Laurent Fabius said his country was justified in taking action in Syria. "It was normal to take the initiative and action and France had the legitimacy to do so. We did it already in the past, we have conducted new airstrikes in Raqqa today," Fabius said. "One cannot be attacked harshly, and you know the drama that is happening in Paris, without being present and active."

The air raids came after President Francois Hollande called the Paris attacks – the worst in the country's history – an "act of war" and vowed to hit back "without mercy."

Meanwhile, a prominent anti-DAESH group, Raqqa is Being Slaughtered Silently, said on Twitter that no civilians were killed or wounded by the French strikes, citing sources in local hospitals. The group also said airstrikes hit a stadium, a museum, clinics, a hospital and a local government building, adding that water and electricity were cut for a while because of the airstrikes. However, some claimed that civilians have been killed as well.

World leaders earlier united Sunday to denounce terrorism at a heavily-guarded G20 summit in Turkey and observed a minute's silence in respect of those who were killed.

Last week France had attacked oil depots controlled by the terrorist group.

France did not participate in the coalition's anti- DAESH attacks in Syria from September 2014 to September 2015, arguing that they would strengthen the Assad regime.