The leaders of Russia and Turkey have announced an agreement for their two countries' forces to jointly patrol almost the entire north-eastern Syrian border after the withdrawal of Kurdish fighters.

Key points: Under the deal, Kurdish fighters would have 150 hours to withdraw from the border

Under the deal, Kurdish fighters would have 150 hours to withdraw from the border Russia's Foreign Minister Sergey Lavrov said the deal implied an end to the Turkish offensive

Russia's Foreign Minister Sergey Lavrov said the deal implied an end to the Turkish offensive Turkey plans to settle millions of Syrian refugees in the zone created near the border

Presidents Vladimir Putin of Russia and Recep Tayyip Erdogan of Turkey announced their agreement after six hours of talks and poring over maps of Syria at the Black Sea resort of Sochi.

The announcement came as Kurdish fighters completed their pullout from a section of the Syrian-Turkish border as required by a US-brokered ceasefire that was set to expire Tuesday night (local time).

The deal would seal Turkish and Russian power in Syria, filling the void left by departing American troops after President Donald Trump abruptly ordered their withdrawal.

After receiving news of the Kurdish withdrawal, the Turkish defence ministry said in a statement there was no need to initiate another operation.

US Special Envoy James Jeffrey said Turkey's military had agreed to a more permanent "pause" in the fighting.

"We're in a better place now than we were a week ago," Mr Jeffrey told a Senate hearing.

"In looking at this ceasefire, I think we have done a pretty good job in bringing this conflict to a halt."

But Democrat Senator Bob Menendez said the withdrawal had "sidelined" the US, increased the threat of terrorism and "solidified Russian and Iranian political and military power across Syria and beyond".

"Russia and the murderous Assad regime are calling the shots," he said at the Senate hearing.

"If there was any doubt before, [Mr] Erdogan's intentions are clear: an ethnic cleansing mission in Northeastern Syria at the expense of broader regional stability, including the fight against ISIS, and of partnership and cooperation with the United States and other NATO allies."

Russian and Syrian border patrols to start immediately

Turkish troops and Turkish-backed Syrian fighters launched their offensive against Kurdish forces two weeks ago. ( AP )

Under the 10-point deal, Kurdish fighters would have 150 hours starting at noon on Wednesday (local time) to withdraw from the border.

Russian and Syrian Government forces would move into that area immediately to ensure the Kurdish fighters pull back 30 kilometres from the border.

Then at the end of the 150 hours, Russian-Turkish patrols would begin along a 10-kilometre wide strip of the border.

The exception would be the region around the town of Qamishli at the far eastern end of the border, which has some of the densest Kurdish population.

Russian and Turkish officials did not immediately say what the arrangement would be around Qamishli.

"I believe that this agreement will start a new era toward Syria's lasting stability and it being cleared of terrorism," Mr Erdogan said.

"I hope that this agreement is beneficial to our countries and to our brothers in Syria," he said.

Together the arrangements transform the map of north-east Syria, leaving Turkey in sole control over one section in the middle of the border, while Turkey, Russia and the Syrian government will have hands in the rest.

The deployments replace American soldiers who for five years battled alongside Kurdish-led fighters and succeeded in bringing down the rule of the Islamic State group across a third of Syria at the cost of thousands of Kurdish fighters' lives.

Russia's Foreign Minister Sergey Lavrov said the implied an end to the Turkish offensive in north-eastern Syria. ( Reuters: Murad Sezer )

Deal aims to 'end bloodshed'

Russia's foreign minister Sergey Lavrov said a deal between Russia and Turkey implied an end to the Turkish offensive in north-eastern Syria.

He said the agreement reached by Russian and Turkish presidents in Sochi meant "ending bloodshed, ending the operation that drew contradictory reaction in the world."

Redur Khalil, a senior Kurdish official, confirmed his forces had entirely left that area.

But he said Turkish troops and their allies were continuing military operations in north-eastern Syria outside that withdrawal zone.

Turkey also plans to settle many of the 3.6 million Syrian refugees on its soil in that zone, which is the heartland of Syria's Kurdish minority.

For the Kurds, a Turkish takeover would mean the crushing of the self-rule they have carved out in the north-east amid Syria's civil war.

The Kurdish Red Crescent said at least 200,000 people have been displaced by the Turkish invasion of northern Syria. ( AP: Baderkhan Ahmad )

They also fear massive demographic change, as Kurdish civilians flee Turkish control and mainly Arab Syrian refugees move in.

The new agreement aimed to ease those fears by giving Russia and its ally, the Syrian government, control over much of the area, with the Turkish patrols limited to closer to the border.

That might prevent a massive flight of civilians but would be a heavy blow to Kurdish autonomy dreams.

ABC/wires