Egyptian police fired teargas at Islamist students who pelted them with rocks during an anti-army protest in Cairo's Al-Azhar university on Sunday, an AFP reporter and the interior ministry said.
About 3,000 students initially blocked the main Nasr road leading to the Islamic university's campus, and clashed with police who arrived to persuade them to leave, the ministry said in a statement.
An AFP reporter said police later dispersed the students, who pressed their protest. The ministry said police fired teargas at demonstrators.
A security official said no casualties were reported in the clashes.
A similar demonstration took place in Cairo University where scuffles broke out between supporters and opponents of ousted Islamist president Mohamed Morsi, a security official said.
Islamists who reject the military-installed government have regularly staged protests against the army, which toppled Morsi on July 3 after millions took to the streets demanding his resignation.
More than 1,000 people, mostly Morsi's backers, were killed in clashes in the ensuing crackdown on the former president's Muslim Brotherhood movement.
Another 2,000 people, mostly Islamists, have been detained.
Morsi, held at an unknown location since his ouster, will stand trial next month over deadly clashes between his supporters and opponents outside his palace in December 2012.