France wants UN Security Council action on Syria chemical weapons' use

France said on Tuesday the United Nations Security Council had to respond over the use of chemical weapons in Syria with a resolution that would punish those responsible for repeated attacks.

Syrian government forces used chemical weapons in opposition-controlled parts of Aleppo during battles to retake the city late last year, Human Rights Watch (HRW) said in a report published on Monday.

The findings add to mounting evidence of the use of banned chemical weapons in the six-year-old Syrian civil war and could strengthen calls by Britain, France and the United States for sanctions against Syrian officials.

While not confirming the report, a French foreign ministry spokesman said in a daily briefing the allegations were "extremely serious."

"It is up to the Security Council to act. France ... continues to discuss with its partners at the Security Council to adopt a resolution to punish those responsible for these attacks," the spokesman said.

"The use of weapons of mass destruction constitute a war crime and a threat to peace. Impunity is not an option."