REBELS in Syria shelled the United Nations office and other civilian buildings in Aleppo yesterday, killing more than 40.

UN resident representative in Syria Ali al-Za’atari said the office was hit by insurgent tank fire, damaging the upper floors.

And militants positioned in the city’s Bustan al-Qaser shelled the Shahba Hotel and nearby residential buildings, causing extensive damage and casualties.

Those casualties added to the 84 west Aleppo residents dead and 280 injured announced by the Syrian Defence Ministry on Monday since the start of a major anti-government offensive in the city on Friday.

But despite yesterday’s shelling, the assault by Syria’s al-Qaida — now rebranded the Levant Conquest Front — and Western-backed factions under its command seemed to be running out of steam.

The 8,000 extremists gathered for the campaign have so far made only limited inroads in the al-Assad and Minyan districts on the city’s western edge.

To the north-east, the army has pushed Islamic State (Isis) back, allowing Kurdish YPG militia to take a string of villages as they race the Turkish-backed Free Syrian Army to the strategic town of al-Bab.

Turkey halted air raids on the YPG last week, which an unnamed military source told Turkish media was in response to threats from Syria to shoot down invading jets.

Russian Defence Minister Sergei Shoigu said the 2,000-odd so-called moderate occupiers trapped in east Aleppo were abusing humanitarian truces.

“Militants shoot dozens of civilians every day for trying to approach the humanitarian corridors.

“Is that the opposition it is possible to hold negotiations with?” he asked. “The gunmen use this for their own benefit.

“As a result, the prospects for the beginning of the political process and the Syrian people’s return to peace are postponed indefinitely,” he said.

Mr Shoigu added that an aircraft carrier, heavy missile cruiser, two destroyers and three cruise missile-armed submarines entered the Mediterranean last week. He said they were ready to join the fight against foreign terrorists and mercenaries in Syria, despite Nato pressuring member states not to allow the vessels to refuel.

“It is time for our Western colleagues to decide who they are actually fighting: terrorists or Russia,” Mr Shoigu said.