The Syrian army said it had taken control of an important district in rebel-held eastern Aleppo on Saturday after fierce fighting, with rebels blaming intense air strikes and lack of hospitals for their collapsing frontline.

Government forces advanced with a ground and air assault on the edge of the besieged eastern half of the city, a move the rebels say is designed to split their most important urban stronghold in two.

Aleppo, which was Syria’s biggest city before the start of a civil war that has killed hundreds of thousands of people, is divided between the government-held west and rebel-held east, where U.N. officials say at least 250,000 people are under siege.

Capturing all of Aleppo would be a major victory for Syrian President Bashar al-Assad after six and a half years of fighting.

The army said in a statement it had, alongside its allies, taken full control over the Hanano housing district, which is on the northeast frontline of the eastern sector.

“Engineering teams are removing mines and improvised explosive devices planted by terrorists in the squares and streets,” the statement said. The Syrian government calls all forces fighting against it terrorists.

Hundreds of men vanish as they flee Aleppo, U.N. official says

Read Next: Hundreds of men vanish as they flee Aleppo, U.N. official says

Featured image courtesy of BBC.