Syrian state media say a rocket slammed into a building in the country's northern city of Aleppo on Friday, causing casualties.

Video broadcast on state television showed large parts of the building collapsed, with medics pulling bodies out of the wreckage. The number of dead and wounded is not immediately known.

State media have blamed the attack on a “terrorist group”, a term it frequently uses to describe rebels in the 22-month-old uprising against President Bashar al-Assad. But activists say the government launched a military airstrike in the area.

Syria's government restricts foreign media from many parts of the country, making it difficult to confirm details of attacks.

Aleppo, Syria's commercial hub and the country's largest city, has been wracked by violence since rebels launched an assault on the city in July 2012.

Earlier this week, twin blasts at Aleppo University killed 87 people and wounded more than 150. Among the dead are students and refugees who had settled at the campus. Each side has blamed the other for that attack.

The Syrian conflict has killed at least 60,000 people since it began in March 2011.