Turkish and Iranian top diplomats held a phone call on Saturday about preparations for an upcoming high-level meeting, the Turkish Foreign Ministry said in a statement on Saturday.
Foreign Minister Mevlüt Çavuşoğlu and his Iranian counterpart Hossein Amirabdollahian held the call after the Iranian foreign minister paid an official visit to Turkey on June 27.
The presidents of the three guarantor states of the Astana process on Syria, Recep Tayyip Erdoğan of Turkey, Ebrahim Raisi of Iran and Vladimir Putin of Russia, are expected to hold a trilateral meeting in Tehran later this month.
The Astana talks for peace in Syria were launched in 2017 at the initiative of these three countries. Its meetings also contribute to the advancement of the United Nations-led diplomatic process in Geneva.
Putin will travel to Tehran on July 19 for a Syria summit with Erdoğan and Raisi, the Kremlin announced Tuesday.
"The president's visit to Tehran is being planned for July 19," Kremlin spokesperson Dmitry Peskov said. He said the trio would meet for peace talks on Syria.
Russia, Turkey and Iran have in recent years been holding talks on Syria as part of the called the "Astana peace process" to end more than 11 years of conflict in the Middle Eastern country.
It will be the Kremlin chief's second visit abroad since he sent troops into Ukraine in late February, after having visited Tajikistan in late June.
The Kremlin said Putin will also hold separate talks with Erdoğan in Tehran, without providing more details.
Russia and Iran are the key military and political backers of the Syrian regime leader Bashar Assad, while Turkey has provided military assistance to the Free Syrian Army and other opposition groups still fighting against Assad's forces in northwest Syria.
The Kremlin had said on Monday that Putin and Erdoğan, who has been mediating between Moscow and Kyiv since Russia sent its armed forces into Ukraine on Feb. 24, would hold in-person talks soon after a phone conversation in which they discussed efforts to facilitate grain exports from Ukraine. Peskov made no mention on Tuesday of any bilateral meeting between Putin and Raisi in Tehran.
The 18th round of the international meeting on Syria in Astana format was held on June 15-16 in Nur-Sultan, the capital city of Kazakhstan.
According to the Turkish Foreign Ministry, during the Astana peace talks, the situation on the ground, counterterrorism, the latest developments in the political process and humanitarian aid issues were discussed, and a joint statement was released.
The Turkish Foreign Ministry said the parties stressed their strong commitment to Syria's political unity and territorial integrity and the leading role of the Astana process in the peaceful settlement of the Syrian issue.
They voiced their determination against the separatist agendas that pose a threat to the national security of neighboring countries, including through cross-border attacks and infiltrations.
The parties also condemned the increased presence and activities of terrorist groups and their affiliates under different names in Syria. They underlined the necessity to implement all arrangements related to the north of Syria.
They said that all attempts to create illegitimate self-rule initiatives under the pretext of combating terrorism are unacceptable. They condemned the actions of countries that support terrorist entities, including illegitimate self-rule initiatives in the northeast of Syria.
"The parties expressed grave concern with increasing hostilities and all forms of oppression by the separatist groups against civilians in the east of Euphrates, including through suppression of peaceful demonstrations, forced conscription and discriminatory practices in the field of education," the Turkish Foreign Ministry said.
"In this context, our determination in combatting against PKK and its Syrian branch YPG terrorist organization as well as in taking every measure to protect our borders, to prevent attacks against our people, our security forces, and innocent Syrian civilians was emphasized," it added.
Moreover, the parties reaffirmed their commitments to achieving progress in the process of the political settlement of the Syrian conflict in line with the U.N. Security Council Resolution 2254.
In this context, they called for the subsequent round of the Constitutional Committee to be held with the constructive approach of the Syrian parties.