The defence ministers and intelligence chiefs of Iran, Russia, Syria and Turkey held talks on Tuesday that Ankara and Moscow described as constructive, as part of efforts to rebuild Turkey-Syria ties after years of animosity during the Syrian war.
NATO alliance member Turkey has backed political and armed opposition to Syrian President Bashar al-Assad during the 12-year civil war, and sent its own troops into the country's north.
Moscow is Assad's main ally and Russia has encouraged a reconciliation with Ankara. But Damascus demands the full withdrawal of Turkish troops for relations to be restored.
At the talks in Moscow, the ministers and intelligence service chiefs discussed strengthening security in Syria and the normalisation of ties between Ankara and Damascus, the Turkish and Russian defence ministries said in separate statements.
All four countries reaffirmed their desire to preserve Syria's territorial integrity and the need to intensify efforts for the speedy return of Syrian refugees to their country, the statements said.
The Syrian defence ministry said the talks discussed the withdrawal of Turkish troops from Syria alongside opening the strategic M4 highway that paves the way for the revival of Syria's trade with neighbouring countries.
The Syrian and Turkish defence ministers previously held talks in Moscow in December, marking the highest-level encounter between the two countries since the war began.
Turkey's foreign minister last week said that a meeting of foreign ministers of the four countries that would build on the December talks may take place in early May, but he later said it was postponed because the parties could not agree on an exact date.
Syrian officials have repeatedly said that any moves towards normalising ties between Damascus and Ankara can only come after Turkey agrees to pull out thousands of troops it has stationed in the rebel-held northwest.
Turkey's extensive military presence has prevented previous Russian-led military campaigns from restoring the last major rebel-held enclave in Syria back under state control.
(Reporting by Ece Toksabay and Huseyin Hayatsever and Maya Gebeily in Beirut; Editing by Daren Butler, Barbara Lewis and Jonathan Oatis)
