ANKARA, Turkey — Syrian rebels finished withdrawing all their heavy weapons from the front lines in the northwestern province of Idlib on Monday, Turkey's state-run news agency said, quoting unnamed opposition figures and Turkish officials.

The Anadolu Agency did not provide further details on the move, which came as part of a deal reached between Russia and Turkey to demilitarize the front lines between Syrian government forces and the opposition in and around the province. Idlib is the last major rebel stronghold in Syria.

Naji al-Mustafa, spokesman for the National Front for Liberation, a Turkish-backed umbrella group, said Sunday the alliance had unanimously agreed to implement the deal reached last month and expected to demilitarize 15-20 kilometers (9-12 miles) along the front lines by Oct. 15.

He said opposition forces would keep forward bases and light and medium weapons in place.

The Britain-based Syrian Observatory for Human Rights reported Monday that nearly all heavy weapons have been removed from much of the area around Idlib.

The Observatory's chief, Rami Abdurrahman, said that even al-Qaida-linked militants and other jihadis are withdrawing their heavy weapons, hoping to avoid a confrontation with Turkish troops and allied Syrian fighters.

The group said that in some areas, jihadis hid their heavy weapons on the western edge of Idlib near Latakia province in covered trenches.

"The demilitarized area agreed upon between Russia and Turkey is almost empty of heavy weapons," the Observatory said.

The al-Qaida-linked Levant Liberation Committee, the largest armed group in Idlib, has not said whether it will comply with the deal.