United Nations secretary-general Antonio Guterres on Tuesday said he was "outraged" by reports of a chemical weapons attack in the Syrian town of Douma and urged the UN Security Council to "find unity" in a vote on US and Russian draft resolutions on the incident.
"I am outraged by the continued reports of use of chemical weapons in the Syrian Arab Republic," Guterres said in a statement.
"I reiterate my strong condemnation of the use of chemical weapons against the civilian population. Any confirmed use of chemical weapons, by any party to the conflict and under any circumstances, is abhorrent and a clear violation of international law.
Guterres said he fully supported the fact-finding mission by the Organisation for the Prohibition of Chemical Weapons which the OPCW said on Tuesday would deploy to Syria "shortly".
The mission should be granted full access to the site of the alleged chemical attack "without any restrictions or impediments to perform its activities," Guterres said.
"The norms against chemical weapons must be upheld. I appeal to the Security Council to fulfil its responsibility and find unity on this issue. I also encourage the Council to redouble its efforts to agree on a dedicated mechanism for accountability."
"I stand ready to support such efforts," he concluded.
The US draft Security Council resolution wants a new panel to be set up that would investigate and apportion blame for chemical attacks in Syria, but Russia is likely to veto the proposal. Syria and its military backer, Russia, both said they wanted to facilitate a visit by inspectors.
Syria denies being behind any chemical attack.
Dozens were killed in the alleged chemical attack on the rebel enclave of Douma in Eastern Ghouta outside Damascus and but exact numbers are impossible to verify. International humanitarian organisations have not been allowed to enter Douma since early March due to a government's siege.
US president Donald Trump has pledged a "forceful" response to the Douma attack, and has spoken of numerous military options.
After a Sarin nerve agent attack killed more than 80 people in a Syrian opposition-held town last April, Trump ordered the firing of dozens of cruise missiles at a Syrian government air base from US Navy ships in the Mediterranean.
It was the first direct US military action against forces commanded by Syrian president Bashar al-Assad.
