DAMASCUS, March 22 (Xinhua) -- A key rebel group controlling the central part of Damascus' Eastern Ghouta countryside declared Thursday a ceasefire to negotiate its withdrawal from the region, local media reported.

The War Media, the media wing of the Syrian army, reported that the Failaq al-Rahman rebels, or the Rahman Legion, declared a ceasefire in the central part of Eastern Ghouta, namely in the areas of Jobar, Zamalka, Ayn Tarma, Hazzeh, and Arbeen, as of midnight Friday.

These areas have been the launching pad for the Failaq al-Rahman rebels for firing mortar and rocket shells on the Syria capital of Damascus throughout the last seven years of crisis.

This development came as the Syrian army captured the farms of Ayn Tarma on Thursday and advanced toward that area, which is a key stronghold of the Failaq al-Rahman rebels.

The negotiation for withdrawal coincided with the evacuation of the Ahrar al-Sham rebels from Harasta city, also a key rebel stronghold in Eastern Ghouta.

As many as 1,580 people, including rebels and their families, evacuated Harasta on Thursday evening as hundreds more are set to leave that area toward rebel-held areas in the northwestern province of Idlib.

The Syrian army has already captured over 80 percent of Eastern Ghouta and is closing in on the remaining rebel-held areas amid ongoing military offensive.

The alliances of Failaq al-Rahman have been murky in Eastern Ghouta, as in many cases it was allied with the al-Qaida-linked Nusra Front, according to the state media in Syria.

If the group evacuated Eastern Ghouta, it would be a major victory for the Syrian army and a massive setback for the rebels' presence in Eastern Ghouta, the last remaining threat to the capital.