Syrian President Bashar al-Assad said on Thursday he would only meet his Turkish counterpart Recep Tayyip Erdogan if Turkey withdrew its troops from northern Syria and the situation returned to what it was before the Syrian revolution.
Turkey is the biggest military and political ally of the Syrian opposition, which controls its last stronghold in northwestern Syria. Ankara has established dozens of military bases and deployed thousands of troops to northern Syria, preventing the Russian-backed Syrian army from regaining control of the area.
Assad, who is visiting Moscow for talks with Russian President Vladimir Putin, said in an interview with Russia's Sputnik that there was no point in meeting until Turkey ended the "illegal occupation."
He added that Turkey should "stop supporting terrorism", referring to the opposition that controls areas of northern Syria, some of which receive training and support from Turkey.
In the interview, Assad acknowledged Russia's role in encouraging rapprochement with Erdogan.
He noted that the presence of Russian troops in Syria was legitimate because his government had asked for Moscow's support.
Diplomats from Iran, Russia, Turkey and Syria are due to meet in Moscow this week in preparation for a meeting of their foreign ministers, Turkish media reported.
Recep Tayyip Erdogan and Bashar al-Assad established friendly relations in the first decade of the 21st century after years of disagreements between their countries.
But the Syrian regime's suppression of the March 2011 revolution plunged the country into a civil war that left some 500,<> dead and millions displaced, and strained relations between Damascus and Ankara, which backed anti-Assad factions.
At the end of December, the Turkish and Syrian defense ministers met in Moscow in the presence of their Russian counterparts for the first time since 2011.