Four sources said that Turkish intelligence chief Hakan Fidan held several meetings with his Syrian counterpart in Damascus during the past few weeks, in an indication of the progress of Russian efforts to thaw the ice between the two countries that are on opposite sides of the Syrian war.

A regional source loyal to the Syrian regime told Reuters that the head of the Turkish National Intelligence Service and the head of Syrian intelligence, Ali Mamlouk, met a few days ago in Damascus.

Turkish officials and the regional source said these contacts reflect a shift in Russian policy at a time when Moscow is preparing itself for a long-running conflict in Ukraine, while seeking to secure its position in Syria, where its forces have supported President Bashar al-Assad since 2015.

Turkish support is a key factor for the Syrian opposition to maintain its last major foothold in the northwest, after the Assad regime regained large areas, with the help of Russia and Iran.

But the rapprochement collides with many complications, including the fate of opposition fighters and millions of civilians, many of whom fled to the northwest to escape Assad's rule.

According to a senior Turkish official and security source, Mamlouk and Fidan discussed, during recent meetings, the possibility of a meeting between the foreign ministers of the two countries at the end.

"Russia wants Syria and Turkey to transcend their differences and reach specific agreements ... that are in everyone's interest, including Turkey and Syria," the Turkish official said.

The Turkish security source said that the recent meetings, including a two-day visit by Fidan to Damascus at the end of August, sought to pave the way for higher-level sessions.

A diplomat based in the region said Russia withdrew a limited number of troops from southern Syria earlier this summer, particularly areas along the border with Israel that were later occupied by forces allied with Iran.

According to Reuters, the sources quoted by the statements spoke on condition of anonymity due to the sensitivity of the meetings, which were not publicly disclosed.

The agency noted that the Russian Foreign Ministry did not immediately respond to a request for comment, and the Turkish intelligence service declined to comment, and the Foreign Ministry did not immediately comment.

The Syrian Ministry of Information also did not immediately respond to emailed questions from Reuters.

On August 11, Turkish Foreign Minister Mevlüt Çavuşoğlu sparked a storm of controversy, when he revealed a short conversation he had with the Syrian Foreign Minister, Faisal Miqdad, calling for "reconciliation between the regime and the opposition in some way."

This conversation, conducted by Cavusoglu - on the sidelines of the Non-Aligned Movement meeting 10 months ago in Belgrade - raised doubts about Ankara's desire to abandon its supportive approach to the opposition and demand a political transition in Syria.

Then, Turkish President Recep Tayyip Erdogan stated that his country "has no ambitions" in the territory of Syria, and made it clear that he did not rule out talks between Ankara and Damascus.