MOSCOW (Reuters) - The heads of the Russian and U.S. general staffs discussed the situation in Syria in a phone call on Friday amid mounting tensions over the province of Idlib, the Interfax news agency cited Russia’s Defence Ministry as saying.

The phone call came after the killing of 33 Turkish soldiers in a strike by Syrian government forces in Syria’s northwestern Idlib region on Thursday. Russia is a close ally of the Syrian government. Turkey is a NATO member.