At least 10 were killed as a bus carrying students overturned on Tuesday on the campus of Islamic Azad University in Tehran, Iranian Student (ISNA) news agency reported Wednesday.

A total of 27 others were injured, Peyman Saberian, chief of Tehran Emergency Center, was quoted as saying.

Earlier reports said a number of injured students were in critical condition.

Some reports blamed the brake system of the bus for the deadly accident.

Hossein Abedi, acting police chief of Tehran, told IRNA that the cause of the incident is still under investigation.