Syrian government forces have killed at least 46 civilians in air raids in the northern city of Aleppo, activists say.

The Syrian Observatory for Human Rights (SOHR) says helicopters dropped barrel bombs - essentially barrels packed with explosives - on the city.

Aleppo has been the focus of bitter fighting between President Bashar al-Assad's forces and rebels.

Meanwhile militants linked to al-Qaeda are reported to have killed the leader of a rival Islamist militia there.

Fighters from the Islamic State of the Iraq and the Levant (ISIS) killed Adnan Bakkour during a raid on the base of rivals, the Tawheed Brigades, according to SOHR, a UK-based group that monitors the conflict.
'Liberation'

Attacks using barrel bombs and Scud missiles by President Assad's forces are believed to have killed hundreds of people in Aleppo since the conflict began almost three years ago.

The use of the barrel bombs has been condemned by rights groups as indiscriminate.

Thirty-three civilians, including women and children, died in a bombardment of the al-Bab area of Aleppo on Saturday, while at least 13 were killed in eastern areas of the city, SOHR said.

Rebel fighters were also killed by the bombs.

Russia has blocked statements at the UN Security Council condemning the Syrian government's use of air strikes against civilians in Aleppo.

Syrian government forces have launched an offensive in recent weeks on rebel-held areas in the east of the city, with Defence Minister Gen Fahd al-Freij visiting the province on Friday.

Quoted by state news agency Sana, he praised the army for its "great victories and their liberation of many areas in Aleppo".

More than 100,000 people have been killed and millions forced to flee their homes in Syria's nearly three-year civil war.

bbc