France on Friday accused Syria of doing nothing to reach a peace agreement after almost seven years of war and said it was "committing mass crimes" in the Eastern Ghouta region where 400,000 people are besieged by government forces.

U.N.-led peace talks in Geneva ended on Thursday with U.N. special envoy Staffan de Mistura laying most of the blame for the failure of the round at the feet of the government side.

"The Assad regime never entered in any negotiation since the beginning of the civil war," France's Ambassador to the United States Gerard Araud said on Twitter. "They don't look for a political compromise but for the eradication of their enemies."

Despite being a leading backer of the Syrian opposition, France has sought a more pragmatic approach to the Syrian conflict since the arrival of President Emmanuel Macron, saying that the departure of Syrian President Bashar al-Assad was not a pre-condition for talks.

However, on Friday the lack of progress in Geneva and continuing assault of the besieged rebel enclave of Eastern Ghouta near Damascus brought scathing criticism from Paris.

"There is no alternative to a negotiated political solution agreed by both parties under the auspices of the United Nations," deputy foreign ministry spokesman Alexandre Giorgini told reporters in a daily briefing, reiterating Paris' support for de Mistura and appearing to dismiss a separate Russian initiative planned in Sochi next year.

"We deplore the attitude of the Syrian regime, which has refused to engage in the discussion. The Syrian regime is responsible for the lack of progress in the negotiations," he said.

He also pointed the finger at Russia and Iran, who both back Assad, over their inability to enforce a ceasefire in Eastern Ghouta, which according to a Sept. 15 accord between Russia, Turkey and Iran, is included among several de-escalation zones.

"It is therefore urgent that Russia and Iran, guarantors of the Astana process and allies of the Damascus regime, take steps for the cessation of the bombings and (enable) humanitarian aid to arrive safely and without those who need it being hindered," Giorgini said.

The United Nations says about 400,000 civilians are besieged and face "complete catastrophe" because aid deliveries by the Syrian government were blocked and hundreds of people who need urgent medical evacuation have not been allowed outside the enclave.

"By denying humanitarian access, the Damascus regime is responsible for mass crimes, particularly through the use of the siege as a weapon of war," Giorgini said.