SYRIAN troops took back swathes of east Aleppo yesterday as Washington “backtracked” in talks with Russia.

The army exploited its deep advance on Sunday from the eastern airport to the National Eye Hospital on the edge of the central Old City, seizing large built-up areas north and south of the salient.

To the north, soldiers freed the al-Shaar district. One local source said that insurgents fled the area, which had been left perilously exposed to encirclement after Sunday’s advance.

Troops also reportedly took the Qadi Askar and Tarbet Lala neighbourhoods to the west, edging them closer to their long-defended bastion of the medieval citadel.

And to the south they took the mile-wide Marjeh district and the more sparsely populated Sheikh Lutfi further south, then into Karm al-Dada, which borders the river Queiq.

The advance cuts off the hotly contested southern Sheikh Saeed district, with the entire militant-held part of the Old City almost surrounded.

But the al-Qaida affiliated Levant Conquest Front attacked the north-western suburb of Zahraa with tanks, artillery and suicide vehicle bombs. It was unclear whether the assault was a repeat of two failed bids earlier this year to reimpose rebel control or just

a diversion from the main fight.

China and Russia vetoed a UN security council motion on Tuesday night calling for a week-long ceasefire in Aleppo.

The Syrian Foreign Ministry said yesterday that the government would not give the sectarian forces a chance to “regroup and repeat their crimes,” insisting on a complete surrender.

Russian Foreign Minister Sergey Lavrov said his US counterpart John Kerry had cancelled talks on arranging a surrender.

He said Washington had withdrawn an earlier surrender proposal and substituted it for another which “backtracks and is an attempt to buy time for the militants, allow them to catch their breath and resupply.

“Those who refuse to leave on good terms will be destroyed,” Mr Lavrov insisted. “There is no other way out.”

He said Tuesday’s shelling of a Russian field hospital that killed two medics, named as named as Galina Mikhailova and Nadezhda Durachenko, was planned by the extremists and their foreign backers.

“It’s sad that the Western nations, which talk about their concern for human rights and the humanitarian situation in Aleppo and the rest of Syria, are in reality continuing their policy of supporting radicals and extremists.”