Explosions at the University of Aleppo killed at least 82 people and wounded dozens on Tuesday, according to the Syrian Observatory for Human Rights, reported Reuters.
Syrian state television reported a "terrorist attack" near the university, which is government-run. It was the first day of exams, the state news agency reported.
Rebel activists, meanwhile, reported the explosions were caused by government forces, according to Al Jazeera.
The British-based human rights group posted to Facebook page earlier Tuesday:
"Aleppo province: 15 civilians killed and dozens injured by 2 explosions that shook the area in between the University Residence and the Architecture Building in the southern part of the Aleppo University. The cause of these explosions is yet unknown."
"A cowardly terrorist act targeted the students of Aleppo University as they sat for their midterm examinations. This act killed 82 students and wounded 162 other students," said Bashar Ja'afari, Syria's United Nations envoy, while speaking to the UN Security Council, Reuters reported.
Aleppo, Syria's second largest city has long been a battleground between President Bashar al-Assad's government forces and factions of the Free Syrian Army.
The United Nations says about 60,000 people have been killed in the civil war since peaceful protests in March 2011 became violent.
Here's raw footage of the aftermath: