Syrian government troops and their allies advanced on Friday in a district of western Aleppo captured last month by rebels, a Syrian military source and an insurgent official said.

The Syrian military source said the pro-government forces had completely retaken the al-Minian district and had advanced in the neighboring Dahiyet al-Assad district, both on the western edge of Aleppo.

However, Zakaria Malahifji, a Turkish-based official with the Fastaqim rebel group fighting in Aleppo, said that while the army had advanced in al-Minian, it had not gained complete control over the area.

He added that the army had taken three positions in Dahiyet al-Assad but that battles were under way to regain them.

Each side claimed to have inflicted heavy casualties on the other.

Aleppo has become the most intense front in the civil war pitting President Bashar al-Assad, helped by Iran, Shi'ite militias and Russian air power, against Sunni rebels backed by Turkey, the United States and Gulf monarchies.

The city has for years been divided into a government-held western zone and a rebel-held eastern sector which has been besieged since the summer by the army and its allies.

They began a major offensive to retake the eastern districts in late September and a rebel counter-attack was launched by insurgents based in the countryside west of the city in late October.

This week the army captured the 1070 Apartment Blocks district in southwest Aleppo, a focal point of fighting for months and important because of its position alongside a corridor used by the government into the city's western zone.