Russia and Turkey agreed Thursday on a ceasefire in the de-escalation zone in Syria's northwestern province of Idlib, after talks between Russian President Vladimir Putin and his Turkish counterpart Recep Tayyip Erdogan which lasted for about six hours.

Syrian government troops covered by Russian warplanes on Thursday repelled several massive attacks of militants supported by Turkey in Syria's Idlib, according to the Russian military.

A Turkish delegation will travel to Russia on Monday to discuss the situation in Syria's Idlib province amid mounting fears of a humanitarian disaster there, Turkey's foreign minister said.

The U.N. Security Council is going to receive a closed briefing on the ongoing offensive in the last rebel stronghold in Syria at the request of France and the United Kingdom.

The United Nations remains deeply concerned about the safety and protection of more than 3 million civilians in Idlib in northwest Syria, said a UN spokesman on Monday.