Assad's troops surround Aleppo, killing dozens

Syrian government forces had full control of the Leramun district after heavy clashes, as fighting erupted over neighbouring Bani Zeid, also held by rebels, the UK-based Syrian Observatory for Human Rights reported.

The two areas have been used by rebels to launch rockets into government-held districts in the west of the city.

Aleppo has been roughly divided between government control in the west and rebel control in the east since mid-2012.

In recent weeks, however, regime advances around the city's outskirts have severed the only remaining route into the rebel-held eastern neighbourhoods, effectively trapping hundreds of thousands of people under siege.

Opposition forces have responded by firing barrages of missiles into government districts, reportedly killing scores of civilians.

"The importance of capturing Leramun and Bani Zeid is to stop the missile fire and also to further tighten the siege," said Observatory director Rami Abdel Rahman.

He said government forces had now surrounded Bani Zeid, reporting heavy air strikes in the area and ongoing clashes.

The monitor had no immediate death toll from the fighting.

Government forces cut off the opposition's Castello Road supply route on July 7, when they advanced to within firing range.

They have since tightened the encirclement of the rebel-held east, seizing sections of the road, sparking food shortages and spiralling prices in opposition neighbourhoods.

Syria's Al-Watan daily, which is close to the government, also reported advances in Leramun, an industrial area that once housed scores of factories.

Read more: France calls for immediate humanitarian truce following airstrikes in Aleppo

Government forces have also continued to pound opposition areas of the city, with the 18 dead in barrel bomb attacks on Monday in the al-Mashhad neighbourhood.

	Video: Airstrikes pound Aleppo​

The Observatory had earlier given a death toll of 12.

The dead included two women and a child, as well as a rebel commander who was killed with four members of his family, the monitor said.

It added that the toll was expected to rise further because bodies were still thought to be trapped under the rubble, 24 hours after the devastating attacks.

The Syrian Network for Human Rights emphasised that 300,000 Syrians remain trapped in eastern Aleppo, as the Syrian regime now controls Castello Road.

In a report issued on Tuesday, it said Syria's opposition forces also contributed to the siege by tightly controlling the Sheikh Maksoud neighbourhood and refusing to facilitate the passage of civilians and aid.

The report said that serious violations of international and humanitarian law had taken place since the road was taken, saying that around 99 civilians had been killed since the start of the siege to 23 July.

Those killed included 25 children and sixteen women killed by government forces, and around 28 civilians killed by Russian forces.

"Fighting and violence have escalated across several parts of the country over the last few weeks resulting in widespread civilian deaths, injury and displacement," UN emergency aid official Stephen O’Brien said in a statement to the Security Council on Monday.

"Strikes, by all sides, continue to be launched on and from heavily populated areas from air and ground without regard for civilian presence."

A recent report from the Integrated Regional Information Networks (IRIN) found that 44 percent of those killed in Aleppo were the victim of airstrikes, while around 30 percent of fatalities had been the result of shelling and explosions. 

Around 3,570 Syrians have been killed by airstrikes so far this year.  

Analysts estimate that around 400,000 people have been killed in Syria since the conflict began in March 2011 with anti-government protests that were met by a regime crackdown.