Forces loyal to Syrian President Bashar al-Assad have retaken the important district of Sheikh Saeed in southeast Aleppo from rebels in overnight fighting, a group monitoring the country's conflict said on Monday.

"The army is now in full control of Sheikh Saeed," said Rami Abdel Rahman, the head of the Britain-based Syrian Observatory for Human Rights, which gathers information by means of a network of activists on the ground in Syria.

"Syrian regime forces are now in control of 90 percent" of areas that were once held by rebels in the east of the northwestern city, Syria's second city, a major focus in the country's civil war.

He said government warplanes had been pounding the remaining opposition-controlled districts of Aleppo overnight and into early Monday morning.

Rebels, civilians departing

Rebel groups took over much of the eastern part of Aleppo in 2012. Less than a month ago, Syrian army forces and allied militia, backed by airstrikes conducted by Russia, began a major offensive to retake the city. At least 413 civilians have been killed during the operation, according to the Observatory, while 139 have been killed by rebel rocket fire on the western districts of the city.

Russia, which joined the fray as an ally of Assad more than a year ago, said on Monday that 728 Syrian rebels had laid down their arms and relocated to western Aleppo in the past 24 hours.

The Defense Ministry said that 13,346 civilians fled from rebel-controlled districts over the same period.

The Russian-backed offensive to retake Aleppo has drawn criticism from around the world, with rights groups highlighting the plight of civilians trapped in the eastern parts of the city, who have been suffering from severe shortages of basic supplies, including food and water.

Regime setback

The government success in Aleppo is counterbalanced by a loss of territory in the east of the country, with jihadist group so-called "Islamic State" on Sunday recapturing the ancient desert city of Palmyra in the face of fierce Russian airstrikes.

The weekend saw intense fighting in which the extremist militants, who re-entered the city on Saturday after being driven from it once before in March, were at first forced to withdraw under aerial bombardment, before they regrouped and pushed into the city center once more.

The governor of the province of Homs, where Palmyra is situated, said the militants had brought in reinforcements from their stronghold of Raqqa and from Deir Zor province bordering Iraq.

Rebels said that Syria's army had possibly overstretched itself in its focus on Aleppo, diverting resources that would have been needed to defend Palmyra.

The city, a UNESCO World Heritage site, was first overrun by IS militants in May of last year. The extremist Sunni group caused severe damage to many historic artifacts and monuments in the city, considering them to be "idolatrous."

The recapture of the city in March received much international attention, with Russia even staging an orchestral concert in the ancient Roman theater from the second century.

tj/msh (AFP, Reuters)