The deputy foreign ministers of Russia, Turkey, Syria and Iran are meeting in Moscow next week, Turkish Foreign Minister Mevlut Cavusoglu said on Wednesday, ahead of planned talks between foreign ministers later.
Cavusoglu said his Iranian counterpart Hossein Amirabdollahian wanted to join the talks between Turkey, Syria and Russia, and Turkey happily agreed.
"Astana is the only surviving format (to address) Syria anyway. Now we are planning a meeting between the four foreign ministers," Cavusoglu told a joint news conference with Amirabdollahian.
"Russia offered to host a preliminary meeting for the preparations of this four-way meeting. This meeting will be held at the level of deputy ministers next week in Moscow."
Moscow is supporting a rapprochement between Damascus and Ankara, hosting talks between their defence ministers in December and aiming for meetings between the foreign ministers and eventually presidents.
Turkey has been a major backer of the political and armed opposition to Assad during the 12-year-long Syrian conflict, which began with the Assad regime's brutal suppression of pro-democracy protests.
Ankara has sent its own troops into swathes of the country's north and backs rebels there.