A suspected chemical attack killed dozens of people in a rebel-held area of Syria on Tuesday, activists said, describing an incident that would mark one of the worst of its kind in Syria's six-year civil war.
At least 83 people - including 25 children - died and at least 350 others were injured in the incident in northern Idlib province, southwest of Aleppo, the relief agency UOSSM told NBC News.
UOSSM, formally known as the Union of Medical Care and Relief Organizations, is a nonprofit coalition of groups treating to victims of the war in Syria.
President Donald Trump said the attack was "reprehensible and cannot be ignored by the civilised world."
He blamed it on the regime of Syrian President Bashar al-Assad and the Obama administration's "weakness and irresolution" to act after initially citing the use of chemical weapons as a "red line."
The Syrian government denied any involvement and said it was complying with an international Chemical Weapons Convention that bans such instruments of war, according to SANA, the Syrian state-run news agency.
Instead, the government blamed "armed terrorist organisations" for the attack.