Russian war planes struck rebel held areas north of Aleppo on Saturday as the army shelled the besieged old quarter in a major offensive, rebels and a monitoring group said.

 

The air strikes focused on major supply lines into rebel-held areas - the Castello Road and Malah district - while fighting raged in the Suleiman al Halabi neighborhood, the front line to the north of Aleppo's Old City.

 

An army source quoted in state media said its forces had made advances, which was denied by rebels who say they had repelled a new assault.

 

"They are shelling the old city heavily after another failed attempt to gain ground. They have lost several fighters and we are steadfast," said Abu Hamam, a rebel from the Failaq al-Sham group.

 

The Syrian Observatory for Human Rights, a British-based group that monitors the war, reported heavy bombardment by government forces and "back and forth" fighting in the Suleiman al-Halabi neighborhood.

 

The army said it would press its advantage after retaking the strategic Handarat camp north of Aleppo on Thursday.

 

On Friday, civil defense sources said air strikes on rebel held residential areas killed at least 30 people with the use of incendiary and phosphorous bombs causing extensive damage and fires.

 

The Observatory said at least 20 were killed by sustained Russian and Syrian army strikes and artillery shelling on Friday and into the early hours of Saturday.

 

State media said rebel mortar attacks on government-held Midan and other areas in the city killed at least 20 people.

 

The Syrian military and its allies launched a Russian-backed offensive nearly 10 days ago aimed at capturing rebel-held districts of eastern Aleppo that are home to more than 250,000 people.

 

Aleppo, Syria's largest city and commercial hub before civil war began in 2011, has been divided into government and opposition sectors for four years.