Children collect firewood amid damage and debris at a site hit yesterday by airstrikes in the rebel held al-Shaar neighbourhood of Aleppo, Syria November 17, 2016. [Photo/Agencies]

DAMASCUS -- As many as 400 civilians fled rebel-held areas in Syria's northern city of Aleppo overnight, a monitor group reported Sunday.

The civilians fled overnight toward areas under the government control in western Aleppo, as the Syrian army was advancing in rebel-held areas in eastern Aleppo, according to the Syrian Observatory for Human Rights.

State news agency SANA also reported the evacuation of tens of civilians from the Masaken Hanano.

A day earlier, the military forces retook the Masaken Hanano area, following battles with the rebels' Jaish al-Fateh, or the Army of Conquest, during which assorted kinds of weapons were used amid artillery shelling that targeted the rebels' supply lines in the area, SANA said.

Masaken Hanano is the largest rebel-held district in eastern Aleppo, and was also the first area stormed by rebels in mid-2012.

Observers say capturing the Hanano area will expose the Sakhour neighborhood to the Syrian army, enabling it to isolate the northern part of the rebel-held areas in eastern Aleppo from the southern one.

The Observatory, which says it relies on a network of activists on ground, said the Syrian forces were achieving rapid progress in eastern Aleppo, where over 250,000 civilians are trapped.

For months, the Syrian government and Russia have been urging rebels to leave Aleppo, offering them safe passages to other rebel-held areas in the northwestern province of Idlib.

The rebels, however, turned down all offers, which has resulted in intensified violence.