The withdrawal by rebels of their heavy weapons from a planned buffer zone in northwestern Syria is due to last several days, a Turkish-backed alliance of fighters said Sunday.
The National Liberation Front (NLF) announced Saturday that it has begun withdrawing heavy arms from the zone as part of an agreement between Syrian regime ally Russia and rebel backer Turkey.
The accord, reached on September 17, aims to stave off a massive regime assault on Idlib province, the last major rebel bastion in Syria, by creating a 15 to 20-kilometre (9-12 mile) buffer zone ringing the area.
All rebels in the demilitarised zone must withdraw heavy arms by Wednesday, and radical groups must leave by October 15, under the deal.
"We began to withdraw our heavy weapons from the demilitarised zone to rear positions," NLF spokesman Naji Mustafa told AFP.
"The operation will last several days," he said, adding that the weapons will be held by fighters deployed in positions outside the demilitarised zone.
The NLF is the main Turkey-backed rebel alliance in the Idlib region, but jihadist heavyweight Hayat Tahrir al-Sham (HTS) holds most of the province and the zone.
HTS, led by former Al-Qaeda fighters, has yet to announce its stance on the buffer zone deal.
On Sunday, an AFP correspondent saw NLF fighters on the frontline inside the planned buffer zone on the Idlib region's eastern flank.
They waited in trenches armed with light weapons on a hill in the area of Al-Eis in the southwest of Aleppo province, overlooking the regime-held area of Al-Hader several kilometres (miles) away.
The correspondent did not see any heavy weapons in Al-Eis.
HTS also has positions on the frontline in the area, but the correspondent was not immediately able to verify if they had removed their heavy arms.
On Saturday, a media spokesman for Faylaq al-Sham, one of the NLF factions, confirmed the withdrawal of arms.
Seif Raad said it included pulling back missile launchers, tanks and mortars.
The Syrian Observatory for Human Rights war monitor said the withdrawal of weapons had already started a week ago and would continue for several more days.
Weapons were pulled back in rebel-held areas in the north of Hama province on the border with Idlib and had also been shifted in Idlib province, the Britain-based monitor said.
Turkey has deployed troops in "observation posts" it set up in rebel-held areas of Idlib and neighbouring Aleppo province in recent weeks.