Russia and Turkey to establish joint patrols in Syria's Idlib

"We are basically entering joint patrolling, at least patrolling from two sides," President Vladimir Putin said on the sideline of talks with Turkish President Tayyip Erdogan in Moscow.

Erdogan is visiting Russia to discuss Turkish military operation in Syria as well as Ankara's purchase of Russian-built S-400 air defence system.

Syria's conflict has been a thorny subject in Turkish-Russian relations, where both countries support opposing factions.

At the start of the talks, Erdogan hailed the two countries' coordination, saying the "steps we've taken and will take in Syria are of great importance".

Moscow discussions with Ankara ended without agreement on the issue of Idlib, which is mostly controlled by the Hayat Tahrir al-Sham rebel group, though Putin considered the issue "solvable".

Erdogan, referring to the existence of "terrorist groups" in Syria, with Ankara at war with IS and the Kurdish-led Syrian Democratic Forces.

"Our defense ministry together with the Russian defence ministry are working on the issue and will continue doing so," he said.

In February, the countries failed to agree on military action in Idlib when they held summit talks with Iran in Russia’s Sochi.

There are other continued disagreements between the two states over Ankara's demand for a buffer zone inside Syria to prevent the US-backed Kurdish forces controlling the Turkish border.

The SDF's Kurdish dominated People's Protection Units (YPG) deny links to the Kurdistan Workers Party (PKK), designated as terrorist group by Turkey and the EU.

Monday's visit is the third one for the Turkish leader this year in Russia. It comes amid volatile relations with USA, following Turkey's plan to purchase the S-400 military systems.

Erdogan defended the deal and said it's "done" and reiterated that Turkey will not turn away from it.

"If we sign a deal on an issue, that’s a done deal. This is our sovereign right, no one can ask us to back down."