The United Nations Security Council will meet today to discuss the suspected chemical weapons attack in eastern Syria.
At least 70 people, including women and children, are reported to have died in the rebel-held city of Douma.
It comes as US President Donald Trump condemned as "mindless" and "SICK" reports of the alleged chlorine gas attack.
He earlier tweeted: "Many dead, including women and children, in mindless CHEMICAL attack in Syria. Area of atrocity is in lockdown and encircled by Syrian Army, making it completely inaccessible to outside world. President Putin, Russia and Iran are responsible for backing Animal Assad. Big price......to pay. Open area immediately for medical help and verification. Another humanitarian disaster for no reason whatsoever. SICK!"
Many dead, including women and children, in mindless CHEMICAL attack in Syria. Area of atrocity is in lockdown and encircled by Syrian Army, making it completely inaccessible to outside world. President Putin, Russia and Iran are responsible for backing Animal Assad. Big price...
— Donald J. Trump (@realDonaldTrump) April 8, 2018
....to pay. Open area immediately for medical help and verification. Another humanitarian disaster for no reason whatsoever. SICK!
— Donald J. Trump (@realDonaldTrump) April 8, 2018
French President Emmanuel Macron also vowed a "strong, joint response" during a phone conversation, the White House said yesterday.
It added that the regime of Syrian President Bashar al Assad "must be held accountable for its continued human rights abuses".
There has been no independent verification of the claims - made by the White Helmets rescue service and other opposition-linked medical relief groups - of a chemical attack.
However, the European Union has said the "evidence points toward yet another chemical attack".
Another Video showing cases of suffocation among civilians, mostly children and women, following the chemical attack against the civilians in #Douma city. #AssadHitsDoumaWithChemicals pic.twitter.com/ItEpVLq5zM
— The White Helmets (@SyriaCivilDef) April 8, 2018
Nine countries have called for an emergency meeting of the UN Security Council to discuss the reports: the UK, France, the US, Poland, Netherlands, Sweden, Kuwait, Peru and Cote d'Ivore. The meeting will take place later today.
UK, France, US, Poland, Netherlands, Sweden, Kuwait, Peru and Cote d’Ivore have called an emergency meeting of #UNSC to discuss reports of chemical weapons attack in #Syria. Meeting expected on Monday.
— UK at the UN ???? (@UKUN_NewYork) April 8, 2018
Chemical weapons expert Richard Guthrie has been examining the evidence.
"There is no effective international investigation arrangement at this point, unless the UN Secruity Council can be brought to consensus".