Syrian activists say death toll in blasts at Aleppo university rises to more than 80

A Free Syrian Army fighter aims his weapon during clashes with government forces in Aleppo, Syria, Tuesday, Jan. 15, 2013. Two explosions struck the main university in the northern Syrian city of Aleppo on Tuesday, causing an unknown number of casualties, state media and anti-government activists said. (AP Photo/Andoni Lubaki) (The Associated Press)

A Free Syrian Army fighter displays a damaged ordinance in Aleppo, Syria, Tuesday, Jan. 15, 2013. Two explosions struck the main university in the northern Syrian city of Aleppo on Tuesday, causing an unknown number of casualties, state media and anti-government activists said. (AP Photo/Andoni Lubaki) (The Associated Press)

In this photo released by the Syrian official news agency SANA, Syrian people gather at the site after an explosion hit a university in Aleppo, Syria, Tuesday, Jan. 15, 2013. Two explosions struck the main university in the northern Syrian city of Aleppo on Tuesday, causing an unknown number of casualties, state media and anti-government activists said. There were conflicting reports as to what caused the blast at Aleppo University, which was in session Tuesday. (AP Photo/SANA) (The Associated Press)

Syrian activists say the death toll in two blasts inside the campus of the main university in the northern city of Aleppo has risen to 83.

The Britain-based Syrian Observatory for Human Rights says some of the more than 150 injured in Tuesday's blast are in critical condition.

It says the dead included university students and civilians staying in the university dormitories after being displaced by fighting between forces loyal to President Bashar Assad and rebels seeking to topple his regime.

It's unclear what caused the explosions, with each side blaming the other.