BEIRUT — Syrian government troops and allied militiamen seized more ground in Aleppo’s ancient quarters on Wednesday, further widening their control over an enclave in the divided city that has been in rebel hands since 2012, Syria’s state media and an opposition monitoring group said.

With the latest gains, the endgame for Syria’s largest city, which has been carved up between the government and the rebel side for the past four years, appeared to draw even closer. If Aleppo – Syria’s former commercial hub – is captured by government troops, it would be a turning point in the conflict, putting the four largest cities in Syria and the coastal region back under state control.

Rebel defenses have collapsed rapidly in the face of a massive government assault backed by Russia and thousands of Iranian-backed Shiite fighters. On Tuesday, Syrian government forces captured Aleppo’s centrally located al-Shaar neighborhood from the rebels, security nearly three quarters of the besieged enclave less than two weeks after launching their ground offensive.

The state news agency SANA said Wednesday that Syrian forces established control over two districts north of the Aleppo Citadel in the heart of the city – the Aghiour and Bab al-Hadid neighborhoods – after rebels abandoned positions and retreated further south.

The new gains have choked the rebels, forcing them to pull back to other parts of the Old City, said the Britain-based Syrian Observatory for Human Rights, an activist group that tracks Syria’s civil war, now in its sixth year.