Erdogan said on Tuesday there were plans for a face-to-face meeting with Putin in Istanbul on March 5.

“Putin has other working plans for March 5,” Reuters quoted Kremlin spokesman Dmitry Peskov as saying.

The deaths of the Turkish soldiers strained the relationship between Turkey and Russia, which have worked closely together in Syria. But the countries are now heading toward a potentially major disagreement over the Syrian government's advance in Idlib, the country’s last significant rebel-held area.

Syrian government forces with Russian air support stepped up efforts to take control of Idlib in January. Erdogan has criticized Russia for its part in the offensive, accusing it of breaking the terms of a deal it signed with Turkey to secure a ceasefire in the region in September 2018.

After the Turkish soldiers were killed, Ankara began sending more troops to Idlib and Erdogan threatened military reprisals against Syria and Russia if they continued bombing the province.

Erdogan said on Thursday that the Turkish army and Turkish-backed rebels were making gains in Idlib.

"The developments in Idlib turned to our advantage," he said. "It is impossible for Assad to hold without Russia's support."

Reporter’s code: 50101