Russia's envoy for Syria said Thursday that an agreement was "very close" on a fourth safe zone in the country as a new round of talks began in Kazakhstan on ending the six-year war.

Speaking after negotiations involving regime backers Russia and Iran as well as rebel-supporting Turkey, Alexander Lavrentyev expressed confidence that deals for zones in four parts of the country would be finalised on Friday.

"We are very close to signing an agreement on all these four de-escalation zones," he told journalists in the capital Astana.

The two-day talks are the sixth round of negotiations Moscow has spearheaded this year as it seeks to pacify Syria after its game-changing intervention on the side of leader Bashar al-Assad.

The negotiators are looking to nail down details of a proposed "de-escalation" zone in the northern Idlib province, after Moscow ploughed on with setting up three other safe areas around the country in a move that has seen violence drop.

There are still major disagreements over which force will be sent to police the zone covering rebel-held Idlib -- on Syria's northern border with Turkey -- as Ankara and Tehran jockey for influence.

Russia has so far deployed military police to patrol the boundaries of three zones agreed in the south, in Eastern Ghouta near Damascus, and in part of the central Homs province.

Idlib is the only province in Syria that remains entirely beyond regime control after having been captured in 2015 by an alliance of jihadists and rebels.

The talks were also attended by representatives of the Syrian regime and opposition, the United Nations and observers from the United States and Jordan.

More than 330,000 people are estimated to have been killed in the Syrian war that began in 2011 as anti-government protests and millions have been displaced.

source: AFP