A Turkish delegation will represent the Syrian opposition at the Syrian National Dialogue Congress in Russia's Sochi, sources from the Ministry of Foreign Affairs said Tuesday.

The opposition delegation which arrived from Ankara to Sochi did not want to enter the country and attend the congress as a protest against Assad regime flags, pictures and other symbols placed in the airport and the city, they added.

Therefore, the Syrian opposition delegation gave authorization to the Turkish delegation to attend the congress on their behalf, the sources said.

The meetings from which an announcement regarding the formation of a new constitution commission is expected will be attended by Turkey.

Turkey and Russia, together with Iran, are the guarantor countries that brokered a cease-fire in Syria in December 2016, leading to the Astana talks which run parallel to the U.N.-backed discussions in Geneva to find a political solution to the civil war. The three countries also met in November 2017 to discuss the de-escalation zones in Syria.

In the congress at Sochi, Turkey is represented by Deputy Foreign Undersecretary Sedat Önal. The Russian delegation will be headed by Moscow's ambassador to Syria Alexander Lavrentiev and the Iranian delegation will be led by Deputy Foreign Minister Hossein Jaberi. U.N. Special Envoy for Syria Staffan de Mistura is also attending the summit.

Russia, a key ally of Syria's Bashar Assad, said it had invited 1,600 representatives to the Syrian National Dialogue Congress, but so far only the government and opposition representatives tolerated by it have shown up. The main Syrian opposition body, the High Negotiation Committee, has boycotted the talks.

During the preparations for the Syria peace congress, Turkey has strongly stressed that those who have links to the People's Protection Units (PYD) should not attend the congress. It is reported that people affiliated with these terrorist groups were not invited to the congress.

The Sochi congress, brokered by Turkey, Russia and Iran is supposed to bring the warring sides together to find an ultimate solution to the crisis. In relation to the issue, President Recep Tayyip Erdoğan previously stressed that in this respect a new Syria would be born at the summit.

Also on Monday, Foreign Minister Mevlüt Çavuşoğlu and Russian counterpart Sergey Lavrov spoke over the phone on the Syria process.