Syrian social worker Anas Al Basha during one of his clown acts in Aleppo to cheer up traumatised children. Image Credit: AP

Aleppo: Rebels put up fierce resistance on Friday in a key district of Syria’s battered Aleppo, where a regime offensive has left bodies in the streets and sparked a global outcry.

The government assault on the northern city has spurred a mass exodus of tens of thousands of residents from the opposition-held east and prompted fresh calls by Russia for aid corridors.

President Bashar Al Assad’s forces captured the city’s northeast this week and were focused on seizing Shaikh Saeed, a large district on the city’s southeast edges.

But anti-government fighters put up a strong defence there overnight, rolling back recent government gains, according to the Syrian Observatory for Human Rights.

“The regime and allied fighters... wanted to take this neighbourhood at any cost, because capturing it would allow them to target all remaining rebel-held districts,” said Observatory head Rami Abdul Rahman.

“But rebels put up ferocious resistance, because they knew they would be trapped if Shaikh Saeed fell,” Abdul Rahman added.

The head of the Britain-based monitor said opposition forces were now once again in control of at least 70 per cent of the neighbourhood.

Shaikh Saeed borders the last remaining sections of Aleppo still in rebel hands - a collection of densely populated residential neighbourhoods where thousands have sought refuge from advancing regime forces.

In preparation for street-by-street fighting in these districts, hundreds of fighters from Syria’s elite Republican Guard and Fourth Division arrived in Aleppo on Friday, according to the Observatory.

More than 300 civilians, including dozens of children, have been killed in east Aleppo since the government began its offensive on November 15, according to the Observatory.

According to Syrian state news agency SANA, one civilian was killed and three were wounded Friday in rebel rocket attacks.

An AFP correspondent could hear steady rocket fire on west Aleppo overnight and into Friday morning.

Intermittent clashes on Friday rocked a block of residential buildings on the city’s eastern edges, where advancing regime forces have sought to secure the road leading towards Aleppo’s airport.

The escalation of violence in Aleppo has been met with international outrage, including a warning by the UN that the city’s east could become “a giant graveyard.”

Since Saturday more than 50,000 people have poured out of east Aleppo into territory controlled by government forces or local Kurdish authorities, according to the Observatory.

The loss of east Aleppo - a rebel stronghold since 2012 - would be the biggest blow to Syria’s opposition in more than five years.

Syria’s conflict erupted in March 2011 with protests calling for Assad’s ouster, but it has since evolved into a bloody and highly globalised war.

The violence has killed more than 300,000 people and forced more than half the country’s pre-war population out of their homes.