SOCHI - Russian President Vladimir Putin and his Turkish counterpart Recep Tayyip Erdogan met in Sochi on Monday, with efforts to bring peace to Syria set to dominate the agenda at the Black Sea Resort.
Despite being on opposing sides of the Syrian conflict, Russia and Turkey have been working together since a 2016 reconciliation deal ended a crisis caused by the shooting down of a Russian war plane.
"Our relationship has been restored almost to its full capacity," Putin said ahead of the talks, adding that he was glad to see the Turkish leader.
"I am sure our meeting today will be very effective," Erdogan said.
"The main talking point will be the situation in Syria -- the functioning of de-escalation zones and the continuation of the process of political settlement," Kremlin spokesman Dmitry Peskov said ahead of the meeting.
The pair last met in Ankara in September, when they agreed to push for the creation of a "de-escalation" zone in Syria's key northern province of Idlib, in addition to others already proposed.
Russia, along with Iran, is the key backer of Syrian President Bashar al-Assad. Moscow's military intervention in Syria is widely seen as tipping the balance in the conflict.
Turkey, however, has backed the rebels seeking Assad's ouster.
- 'Mutual need' -
Moscow and Ankara have supported negotiations in Kazakhstan's capital Astana from the start of the year, which have run parallel to talks taking place in Geneva with the backing of the United Nations.
Alexei Malashenko, director of research at the Dialogue of Civilizations institute, said Putin and Erdogan had a "mutual need".
"Russia, which is in a very difficult position (in Syria), simply cannot lose allies there -- they can't even lose partners, let alone allies," he said.
Meanwhile Erdogan is dissatisfied with the West's attitude towards him, Malashenko said, pointing to a deal Ankara has signed to buy S-400 air defence systems from Russia.
The deal, reportedly worth $2 billion (1.7 billion euros), has shocked Turkey's NATO allies.
Malashenko said the economy could also be on the agenda at the talks, as Turkey seeks to regain a leading role in the construction business in Russia.
"It's a meeting of two charismatic people, two people with a very high opinion of themselves, two leaders," Malashenko added, stressing the strength of the presidents' personal relationship.
An apparent agreement at the last talks between Putin and Erdogan saw the release of two leading Crimean Tatar activists who had been sentenced by Russian authorities for their political activities in the peninsula annexed from Ukraine.
Erdogan has pledged to support Crimea's Turkish-speaking Tatar minority.
Russia and Turkey have a record of struggling to overcome a regional rivalry that goes back to the Ottoman Empire and the Romanov dynasty.
Ties between the two countries went through their worst crisis since the end of the Cold War when the Turkish air force shot down a Russian war plane over Syria in November 2015.