Smoke rises after what activists said was an airstrike by forces loyal to Syria’s President Bashar al-Assad in the northwestern city of Ariha, in Idlib province, Syria September 19, 2015.

Syrian pro-government forces and Islamist rebels have agreed to begin a ceasefire from midday on Sunday in three battleground districts, a monitoring group and a local official told AFP.

The truce covers the two remaining villages in Idlib province in the northwest still in government hands and the rebels’ last stronghold near the Lebanese border, the town of Zabadani.

The Syrian Observatory for Human Rights said there was no immediate word on the duration of the ceasefire but the rival sides would continue negotiations for a broader truce.

“Fighters stopped military operations early this morning, but the official ceasefire will begin at noon (0900 GMT),” Observatory chief Rami Abdel Rahman said.

Pro-government forces launched an offensive to try to recapture Zabadani in July, prompting a rebel alliance, including Sunni Muslim extremists of al-Qaeda, to besiege the Idlib province villages of Fuaa and Kafraya, whose residents are Shiites.

A member of Zabadani town council, which has been involved in the truce negotiations, confirmed that the ceasefire was due to go into effect at noon

It comes after the rebels launched one of their fiercest attacks on Fuaa and Kafraya so far.

The assault began on Friday with at least nine car bombs against the outskirts of the two villages, seven of them detonated by suicide bombers.

At least 66 rebels, 40 pro-government militiamen and seven civilians have been killed in the fighting, according to the Observatory.

Sunday’s planned ceasefire marks the third attempt to agree a truce for the three areas. Two rounds of negotiations last month failed to produce agreement.

Stumbling blocks have included the withdrawal of all rebel fighters from Zabadani, safe passage for civilians seeking to leave Fuaa and Kafraya, and food and medical aid for those wishing to stay.