MOSCOW / ASTANA: Russia, Turkey and Iran agreed Friday to hold Syria peace talks in Russia’s Black Sea resort of Sochi next month, a move that the U.N. special envoy for Syria said should be assessed based on its contribution to the mandated political process under the United Nations in Geneva.

Russian news reports cited Kazakh diplomat Aidarbek Tumanov who said that during Friday’s meeting in Kazakhstan’s capital, Astana, the parties agreed to hold the so-called Congress for National Dialogue in Sochi on Jan. 29-30.

Russian envoy Alexander Lavrentyev told the Interfax news agency that the parties have yet to agree on the list of participants.

In an apparent concession to Turkey, Lavrentyev said that the Kurdish Democratic Union Party, or PYD, wouldn’t be invited to take part in the Sochi talks, but that “quite a few” Kurdish representatives will attend.

“We have tried to have the Kurds broadly represented but also make sure that it doesn’t annoy our Turkish colleagues,” he said, according to Interfax. Lavrentyev said the full list of participants will be completed after talks with Turkey and Iran.

Tumanov said the three countries have also decided to set up a working group that will deal with prisoner exchanges and agreed on the need to clear Syrian territory of mines.

The Kremlin said that President Vladimir Putin spoke by phone Friday with Turkish President Recep Tayyip Erdogan to discuss the situation in Syria and the Sochi talks, adding that they voiced hope that the Sochi talks agenda will be agreed upon in Astana.

The Sochi talks will open up a fourth track of talks between parties to the complex conflict in Syria. The U.N.’s own Geneva program has been supplemented by the “technical” talks in Astana brokered by Russia, Iran and Turkey.

Russia periodically opens a third track through Cairo. Egypt has provided a base to Syrian reformists viewed as acceptable to the Damascus government.

“The United Nations maintains its view that any political initiative by international actors should be assessed by its ability to contribute to and support the mandated political process under the United Nations in Geneva,” the U.N. Special Envoy for Syria Staffan de Mistura said in a statement.

De Mistura’s statement said the special envoy reiterates his intention to convene a ninth round of intra-Syrian talks under the U.N. auspices in January.

Head of the Syrian government delegation Bashar al-Jaafari said the congress would “pose a basis for dialogue between the Syrians” and confirmed the government would attend.The opposition was more cautious, although Ayman al-Aasemi, a member of the opposition delegation in Astana, told AFP there was “an openness to the idea of Sochi.”

“It’s not a rejection. We’ve asked for more details – how often it will meet, what’s the essential goal,” said Aasemi, who also credited Moscow with “opening up” during the latest round of talks.

“According to the Russians, the constitution and the elections will be the main topics.”

“We will go back to our popular base and the people we represent in Syria, and see what our interest is in attending this conference. But in my view, it’s better to attend than not attend.”

Syrian senior opposition official Ahmed Tohmeh said he will not make a unilateral decision on whether the opposition will attend the Sochi conference or not, adding that he will have to raise the matter with opposition and rebel leaders in Syria.

Separately, Russian Defense Minister Sergei Shoigu Friday said the military has completed the partial withdrawal from Syria ordered by President Vladimir Putin, ending over two years of active involvement in the conflict.

He said a total of 36 planes and four helicopters have returned to their permanent bases, while 157 motor vehicles were delivered to Russia by sea.

Three battalions of military police and officers of the Russian Center for Reconciliation will remain in Syria, Shoigu added, as well as its two bases in the country.

The Syrian government troops have retaken a string of small rebel-held pockets near the country’s capital and in the northwest in the past two weeks, the Britain-based Syrian Observatory for Human Rights said.

In the southwestern part of Damascus province operations have focused on hilly terrain surrounding the village of Beit Jin, held by rebels for more than four years. Farther north, regime forces have ramped up operations to reach Idlib, held by Hay’at Tahrir al-Sham, from two sides, the Observatory said. Troops are pushing north from a corner of the adjacent province of Hama, as well as from Aleppo province to Idlib’s east. They have seized around 40 towns and villages across the three provinces in recent weeks.