Paris: France called on Tuesday for an emergency meeting of the UN Security Council over a suspected chemical attack in rebel-held north-western Syria that killed at least 58 civilians.

French Foreign Minister Jean-Marc Ayrault described the attack as "monstrous" and added: "I have called for an emergency meeting of the UN Security Council."

Ayrault said "chemical weapons" had been used in the attack and that it was "more proof of the savagery that the Syrian people have been subjected to for so many years."

The attack in the town of Khan Sheikhun left dozens struggling to breathe and displaying symptoms such as foaming at the mouth and vomiting and fainting, the Britain-based Syrian Observatory for Human Rights said.

A hospital in the town where doctors were treating victims of the attack was also bombarded, an AFP correspondent said.