Syrian government forces and their allies have taken control of nearly half of the rebel-held areas of Aleppo, according to statements released in Syria and Russia. The Syrian army's media arm said troops now control 20 square kilometres (nearly eight square miles) of the total 45 square kilometres of east Aleppo.

Syrian state TV said the army and its allies have seized the the eastern Aleppo district of al-Sakhour. Rebels denied the claims, but the Syrian Observatory for Human Rights confirmed that government forces have seized the strategic district, meaning the rebels are now left boxed in mostly in central and southeastern Aleppo, encircled by government territory on all sides.

Capturing eastern Aleppo would be the biggest victory for President Bashar al-Assad since the start of the uprising against him in 2011, and would mean the government would be in control of the country's four largest cities as well as the coastal region. It would be seen as a victory for his allies, Russia and Iran, which have outmanoeuvred the West and Assad's regional enemies through direct military intervention.

With military backing from the Russian air force, Iran, and Lebanon's Hezbollah, Assad has gradually closed in on rebel-held eastern Aleppo this year, first cutting off the most direct route to nearby Turkey before encircling it from the west and then beginning a fierce assault in September.

Rebels say their foreign patrons including the United States have abandoned them to their fate in Aleppo. While some of the rebels in Aleppo received support from states such as Turkey, Saudi Arabia, Qatar and the US during the war, they say their foreign backers have failed them as Assad and his allies unleashed enormous firepower.

Backed by allied militiamen, the army made major advances into eastern Aleppo from the northeast in recent days. Rebel defences swiftly collapsed as government forces pushed into the Hanano district on Saturday (26 November), the first time they have pushed this far into eastern Aleppo since 2012.

The Kurdish YPG militia which controls the Sheikh Maqsoud district of Aleppo moved into at least two of the areas left by rebel forces. Some rebels accused the YPG of conspiring with the government in its advance – a charge made against the Aleppo-based Kurds before and one they have previously denied. The YPG, an ally of the US in the war against Islamic State, has been on the opposite side in Aleppo.

Medical and food supplies have been running short in recent weeks as Syrian warplanes pounded the besieged enclave, rendering all remaining functioning hospitals out of service.

The fighting has forced thousands of residents of eastern Aleppo to flee. Some have gone to the Kurdish-held Sheikh Maqsoud district, others have gone over to government territory, and others have moved deeper into remaining rebel-held areas. Mohammad Sandeh, a member of the opposition city council of Aleppo, told Reuters: "They are going towards the areas that are somewhat further (from the front lines). There's fear that the regime will advance more."