Syrian opposition groups are calling for mass protests a day after a raid by security forces on dormitories at Aleppo University killed four students and forced the closure of the state-run school.

Friday is the day of weekly anti-regime protests in Syria, when thousands of demonstrators regularly take to the street calling for President Bashar al-Assad's ouster.

The university incident sparked outrage in the northwestern city of Aleppo and activists said new protests were expected.

The Syrian National Council opposition group urged students across Syria to stage a strike.

The group also said the international community through its silence was encouraging the Assad regime to continue with its brutal crackdown on dissent. [AP]