Russian President Vladimir Putin and Turkish leader Recep Tayyip Erdogan have praised the strong relationship between their two countries during a meeting in the southern Russian city of Sochi.

Opening the talks on Wednesday, Putin referred in glowing terms to the TurkStream pipeline, which came online last year and through which Russian gas is pumped to markets in Turkey.

This was the Kremlin leader's first in-person meeting since going into self-isolation more than a fortnight ago following a coronavirus outbreak in his staff.

In his comments, Erdogan mentioned the importance of Russian-Turkish cooperation in Syria: "Peace there depends on relations between Turkey and Russia," he stressed.

Ankara remains concerned about the situation in the Syrian city of Idlib, which after more than a decade of civil war, is the last major rebel holdout in Syria.

Russia and Turkey, as the protecting powers of the Syrian government and the rebel militias respectively, agreed on a ceasefire in the contested region in March last year.

While violence in the region has indeed decreased since the ceasefire agreement, there are still frequent clashes and a significant civilian death toll to reckon with.

Putin and Erdogan were also due to discuss the situation in Afghanistan and possible military cooperation between the two countries.

Turkey's refusal to recognize the results of the referendum on the Ukrainian peninsula of Crimea, which was annexed by Moscow in 2014, has been a source of tension between the two countries, though the Kremlin said that the topic was not due to be discussed at Wednesday's meeting.

dpa