Syrian government forces and allied troops have advanced further into rebel-held areas of eastern Aleppo, recapturing some 60 percent of the terrain held by rebels since mid-2012, a group monitoring the country's long-running conflict said on Saturday.

The Britain-based Syrian Observatory for Human Rights said the district of Tariq al-Bab had been taken overnight to Saturday by the Syrian army and allied forces. Recapturing the area means that the road from the government-controlled west of the city to the international airport to the east of Aleppo, also held by the regime, is now open.

"The noose is tightening quickly," said Mohammed Abu Jaafar, a medical official from the besiged area of the city. "Our resources are also running low and beginning to disappear."

According to the Observatory and a Syrian army source cited by the Russian Interfax agency, the rebels shot down a light bomber and killed both pilots above Aleppo. When asked about the reports, Syrian Brigadier General Samir Suleiman said that the army had "no such information."

The assault by government forces has caused more civilians to flee, either to remaining rebel-held districts further to the south, Kurdish-controlled areas, or those held by the government. Some 50,000 people are thought to have left the area so far.

Regime forces moving in 'bit by bit'

Syrian state television also shown buses of people, who had allegedly been staying in other parts of Aleppo and were now heading back to their homes in formerly besieged areas.

"The army is advancing bit by bit according to plan," General Suleiman said.

More than 300 civilians have been killed in the ferocious assault on east Aleppo since November 15, according to the Observatory, with nearly 65 civilians killed by rebel fire in the west during the same period. Government forces have been backed by airstrikes carried out by the Russian air force, Moscow being a long-time ally of Assad.

The growing violence has aroused international outrage, with the UN warning that east Aleppo could become "a giant graveyard."

No end in sight?

Losing eastern Aleppo would by the biggest blow yet to rebels opposed to President Bashar al-Assad in the country's more than 5-year-old war.

However, European Union foreign policy chief Federica Mogherini said on Saturday that she was sure the conflict would continue nonetheless.

UNICEF, the UN's children's agency, says nearly 20,000 children have fled

"I'm convinced the fall of Aleppo will not end the war," she said at a conference in Rome.

At the same meeting, the UN envoy for Syria, Staffan de Mistura, said he hoped some means could be found to prevent the situation in Aleppo degenerating even further.

"I was feeling it would be a terrible battle ending up by Christmas-New Year. I hope the battle will not take place, that there will be some type of formula," he said.

More than 300,000 people have been killed so far in Syria's conflict, which had its roots in peaceful, Arab Spring-inspired anti-government protests in March 2011. More than half of the country's population has been displaced.

tj/jlw Reuters, AFP, AP)