French President Emmanuel Macron and US President Donald Trump are calling for the immediate implementation of a 30-day cease-fire in Syria.
The French presidency's office said in a written statement the heads of state discussed the situation in a phone call today.
Macron and Trump agreed to "work together" for the implementation of the UN Security Council resolution passed last weekend to allow a cease-fire, the transport of humanitarian aid and the evacuation of the injured and sick.
They call on Russia to "put maximal pressure on Damascus' without ambiguity" so that the government commits to respecting the UN resolution.
Macron said the use of lethal chemical weapons, if proven, would lead to a strong response. He said he's extremely vigilant on the issue, the statement said.
Syrian activists say the Turkish air force has hit two positions of pro-government Syrian fighters deployed last week in the Kurdish enclave of Afrin, killing and wounding a number of fighters.
The Britain-based Syrian Observatory for Human Rights says the air strikes took place late yesterday in the village of Jamaa and killed 17 fighters of the force known as the Popular Forces.
The main Kurdish militia in Syria, known as YPG, confirmed the attack in a statement, saying the airstrikes killed and wounded several fighters Turkey's military said Turkish-made ATAK helicopters struck a region in western Afrin, killing nine "terrorists."
It did not provide further details and it was not clear if the airstrikes were in retaliation for the deaths of eight Turkish soldiers killed there yesterday.