Most heavy arms out of planned Syria buffer zone: monitor

Jihadists and Turkish-backed rebels have withdrawn most heavy weapons from territory around Syria's last major opposition stronghold ahead of a Wednesday deadline, a monitor said.

The weapons pullback is the first major test of a truce deal brokered by government-backed Russia and rebel-backer Turkey last month to avoid what the United Nations warned would be the appalling humanitarian consequences of a major government offensive.

Under the agreement, all rebel groups have a Wednesday deadline to withdraw all their heavy weaponry from a 15- to 20-kilometre (nine- to 12-mile) buffer zone along the front line in Idlib province and adjacent areas of the northwest.

By next Monday, the rebel zone's most powerful armed group, the Hayat Tahrir al-Sham (HTS) alliance led by Al-Qaeda's former Syria branch, and other jihadist factions must also withdraw their fighters.

The Syrian Observatory for Human Rights, a Britain-based monitoring group, said the heavy weapons pullout was near complete on Tuesday.

"The buffer zone is now almost empty of any heavy weapons on the eve of the expiry of the deadline," its chief Rami Abdel Rahman said.

The pro-Ankara National Liberation Front said it finished pulling out its heavy weapons on Monday.

HTS and smaller jihadist factions quietly began withdrawing theirs on Saturday in an operation that continued through Monday night, the Observatory said.

HTS, which controls more than half of the rebel zone around Idlib, has not given any formal response to the September 17 truce deal.

But a source close to the group told AFP it had come under irresistible pressure to fall into line to avoid further hardship for the rebel zone's three million residents, many of whom have fled previous bloody government offensives on other parts of Syria.

"Everybody has been forced to agree to the initiative, though reluctantly, so that people can enjoy a bit of security and safety after long years of suffering from the savagery of the regime and its allies," the source said.

The new buffer zone is to be patrolled by Turkish troops from the one side and Russian military police from the other.

The source said HTS was satisfied that the presence of the Turkish troops, whose numbers have been increased in recent weeks, would prevent any Russian-backed government offensive.

Forces loyal to President Bashar al-Assad have retaken swathes of territory in Syria since Russia entered the war in September 2015.

A series of offensives earlier this year saw a succession of longtime rebel strongholds surrender and a similar Russia-back assault had been expected in Idlib before the truce deal was announced last month.

More than 360,000 people have been killed since the civil war erupted in 2011 with the brutal repression of anti-government protests.