According to a French presidency statement, Macron condemned the chemical attacks in a phone call with Trump, during which they "exchanged their information and analysis confirming the use of chemical weapons".

"They instructed their teams to deepen exchanges in the coming days... All responsibilities in this area must be clearly established," added the French presidency’s statement.

According to Macron's office, they also instructed their teams to coordinate their efforts at the UN Security Council on Monday.

The two leaders will discuss the subject again within 48 hours.

Foreign Minister Jean-Yves Le Drian called on Sunday for an emergency meeting of the Security Council over the chemical attack late Saturday by the Syrian regime which killed dozens of civilians.

At least 70 civilians were killed after forces of the Bashar al-Assad regime struck targets in Eastern Ghouta’s Douma district in an attack in which poison gas appears to have been used, according to the White Helmets.