Smoke rises from Bustan al-Basha neighborhood of Aleppo, Syria, October 5, 2016. REUTERS/Abdalrhman Ismail

BEIRUT (Reuters) - Syrian government forces seized around half of a key opposition-held neighborhood in Aleppo on Thursday in a new advance against rebels, the Syrian Observatory for Human Rights monitoring group said.

The British-based Observatory said fighting had been raging in the residential Bustan al-Basha quarter near the city center, one of the frontlines in Aleppo which has been divided for years between government and opposition areas of control.

The Syrian military also said in a statement that its forces had advanced in Bustan al-Basha - though an official in an Aleppo-based rebel group denied there had been a government advance in the area.

Government forces have encircled Aleppo’s rebel-held eastern sector in recent weeks with the use of heavy aerial bombardment and are seeking to recapture the whole city.