Syrian and Russian forces will deploy in northeast Syria to remove Kurdish fighters and their weapons from the border with Turkey under a deal agreed today.
The move expands on a US-brokered ceasefire and underlines the changes in Syria since President Donald Trump announced an American troop withdrawal two weeks ago ahead of Turkey's cross-border offensive.
The deal endorses the return of Syrian President Bashar al-Assad's forces to the border alongside Russian troops, replacing the US troops who had patrolled the region for years with their former Kurdish allies.
Under the agreement between Russian President Vladimir Putin and Turkish President Recep Tayyip Erdogan, the two countries said that Russian military police and Syrian border guards would start removing Kurdish forces from the Turkish border area tomorrow.
On Tuesday, Russian and Turkish forces will jointly start to patrol a narrower strip of land in the "safe zone" that Turkey has long sought in northeast Syria.
After six hours of talks with Mr Erdogan in the Black Sea resort of Sochi, Mr Putin expressed satisfaction at decisions he described as "very important, if not momentous, to resolve what is a pretty tense situation which has developed on the Syrian-Turkish border".
A senior Turkish official described it as an "excellent" deal that would achieve Turkey's long-held goal of a border strip cleared of the Kurdish forces, which Ankara regards as a terrorist organisation because of its links to insurgents inside Turkey.
Last week's US-brokered deal, which technically expired tonight, was limited to the central part of the border strip between the Syrian towns of Tel Abyad and Ras al Ain,where Turkish forces have focused their military offensive.
Under the deal with Moscow, the length of border which the Kurdish forces would be required to pull back from is more than three times the size of the territory covered by the US-Turkish accord, covering most of the area Turkey had wanted to include.
After the Sochi talks, Turkish broadcaster NTV quoted Mr Erdogan as saying the US "has not fully kept its promises" under the temporary truce agreement.