A man carries his mother at a temporary shelter in the Housh Nasri area, east of Damascus, capital of Syria, on March 16, 2018. (Xinhua/Hummam Sheikh Ali)

DAMASCUS, March 17 (Xinhua) -- The Syrian army on Saturday declared a unilateral 24-hour cease-fire in the rebel-held city of Harasta in the capital Damascus' Eastern Ghouta area, the War Media, the media wing of the Syrian army, said in a statement.

The unexpected cease-fire went into effect at 3:00 p.m. local time and will last for 24 hours, said the statement.

It added that the cease-fire aimed at letting civilians evacuate from areas in Eastern Ghouta through a recently-established humanitarian corridor near the Water Resources area in Harasta.

From Harasta alone, 170 civilians left and were taken to temporary shelters near Damascus.

Earlier, the Syrian Observatory for Human Rights said as many as 50,000 people have left rebel-held areas in Eastern Ghouta within the past 72 hours.

The civilians evacuated from areas under the control of the Failaq al-Rahman rebel group southwest of Eastern Ghouta toward government-controlled areas through the Hamouriyeh area which was captured recently by the army.

Eastern Ghouta, a 105-square-km agricultural region consisting of several towns and farmlands, poses the last threat to the capital due to its proximity to government-controlled neighborhoods east of Damascus and ongoing mortar attacks that target residential areas in the capital, pushing people over the edge.

Four major rebel groups are currently positioned in Eastern Ghouta, namely the Islam Army, Failaq al-Rahman, Ahrar al-Sham, and the Levant Liberation Committee, known as the al-Qaida-linked Nusra Front.

The UN humanitarian agencies have sounded the alarm about the worsening humanitarian situation for 400,000 people in that region, where activists said around 1,000 people have been killed since late last month by the heavy bombardment and military showdown in areas of Eastern Ghouta.