Syrian government forces have made major gains in southern Aleppo, state media and activists say, leaving rebels with only a small pocket in the city.
Troops and allied militiamen took full control of the districts of Sheikh Saeed and Saliheen on Monday.
The rebels have now lost more than 90% of the territory they once held in eastern Aleppo in less than a month.
Tens of thousands of people are thought to be still living under siege there, with virtually no food or water.
Russia, which backs the government, says more than 100,000 civilians have been displaced by the fighting – including 13,300 in the past 24 hours – and that 2,200 rebel fighters have surrendered.
Aleppo was once Syria’s largest city and its commercial and industrial hub before the uprising against President Bashar al-Assad began in 2011.
For much of the past four years it has been divided roughly in two, with the government controlling the western half and rebels the east.
Troops finally broke the deadlock with the help of Iranian-backed militias and Russian air strikes, reinstating a siege on the east in early September and launching an all-out assault weeks later.
On Monday, the official Sana news agency cited a military source as saying the army had taken full control of the districts of Sheikh Saad, Shahadin, Karam al-Afandi, Karam al-Daadaa and Saliheen.
The source added that army units were pushing into Kallasa, Bustan al-Qasr and Souq al-Hal, and “chasing down” rebels to Sukkari, Mashhad, Amariya and Ansari.
The Syrian Observatory for Human Rights, a UK-based group that monitors the civil war through a network of sources on the ground, confirmed that Sheikh Saad and Saliheen had fallen but said there was still fighting in Karam al-Daadaa, as well as in neighbouring Fardous.
The group’s director, Rami Abdel Rahman, told AFP news agency that the areas still under rebel control were “very small” and that “they could fall at any moment”.
“The battle for Aleppo has begun to enter the final phase,” he said.
In an interview with the BBC’s Victoria Derbyshire programme, an English teacher inside one of the remaining rebel-held areas, described the conditions as terrible.
“The situation inside the eastern part of Aleppo is literally doomsday,” Abdul Kafi Alhamado said. “Bombs are everywhere, people are running, people are injured in the streets, no-one can dare go to help them, some people are under the rubble.”
Russia has said it is consulting with the United States, which backs the opposition, on the terms of a ceasefire that would follow a full withdrawal of rebel fighters from Aleppo. However, there have been no signs of an agreement so far.
“The Russians are being evasive. They are looking at the military situation. Now they are advancing,” Zakaria Malahifji, an official in the Fastaqim rebel group, told Reuters news agency.
The Syrian Observatory says that at least 415 civilians and 364 rebel fighters have been killed in rebel-held areas since 15 November. Another 130 civilians have died in rebel rocket and mortar attacks on the government-controlled west.