Police forces on Monday night tear-gassed Azhar students who cut off Cairo's Nasr Road in protest against a new food poisoning incident at al-Azhar University.

Thirty-eight students were poisoned after having meals containing bad tuna, the Ministry of Health reported.

More than 540 students had been poisoned a few weeks ago after eating bad food at the university cafeteria.

This prompted a wave of protests which ended with sacking Osama al-Abd, the Azhar University president.

Thirteen ambulances are transporting the sick students to a number of hospitals, the ministry said, adding that there are no reported deaths so far.