CAIRO (AP) — Egyptian security forces fought pitched street battles with dozens of university students outside their Cairo campus Monday, firing tear gas to disperse rock-throwing protesters and prevent their rally from reaching the nearby defense ministry.

Security officials said 25 students were arrested for blocking traffic. A security official said one was carrying shotgun ammunition and a tear gas canister, speaking on condition of anonymity because he was not authorized to brief reporters.

Dozens of students pelted the forces with rocks, some picking up tear gas canisters and lobbing them back. Students, some wearing face masks, used metal bars and garbage cans to build barricades. The students were demonstrating Monday outside Ain Shams University in eastern Cairo as part of a spreading protest movement in universities against the current authorities.

Supporters of ousted Islamist President Mohammed Morsi have been staging near-daily protests since his removal from office in July, concentrating lately on universities. The protests have often ended in violence, with police using tear gas, water cannons and shotguns to disperse demonstrators. Protests have intensified in the Islamic Al-Azhar University and the prestigious University of Cairo.

In response to the steady protests, authorities have passed a highly criticized law banning rallies without prior permits from authorities. It has caused an outcry from non-Islamist youth groups — many of whom were at the forefront of the 2011 uprising that forced longtime autocrat Hosni Mubarak from power, as well as protests against Morsi and the military.

Authorities arrested two dozen of the non-Islamist protesters, including prominent activists, and have sent them to trial for violating the law by protesting it without prior permits in a sign they have little tolerance for any dissent.

In defiance of the law, hundreds of activists rallied Monday near Tahrir Square to commemorate bloody clashes between anti-military protesters and security forces two years ago when at least 17 protesters were killed. The demonstrators, largely secular and liberal groups, marched to the Cabinet building, where the clashes took place in December 2011, demanding that officials and police in charge at the time be brought to trial. The protesters asked for no prior permit for their rally, and authorities didn’t confront them.

The December 2011 clashes were one of the early harsh security crackdowns on post-Mubarak protests. Soldiers and police were filmed dragging women by their hair, stomping on the bare chest of one veiled woman, and lobbing rocks and furniture at protesters. At least 17 were killed in three days of clashes after security forces stormed a peaceful sit-in outside the Cabinet demanding an end to military rule.

At the time, Morsi’s group, the Muslim Brotherhood, stayed away from and criticized the protests which took place during parliamentary elections. The Brotherhood won a majority in those elections.

Raising white flags bearing the faces of those killed during the clashes, the protesters banging drums chanted: “Down with the regime!”

“We are reminding the people that we got no retribution for those killed since 2011,” said Abdullah Shabaan, a 24-year-old protester. “We also want to tell the authorities and (military chief Gen. Abdel-Fattah) el-Sissi that beating and repression will not silence us, or make us stay home.”

After less than an hour, some protesters pelted the police force guarding the Cabinet entrance with rocks— prompting a few rounds of projectiles that ended the rally.

Also Monday, security officials in the Sinai Peninsula said army troops killed a lead militant suspected of being behind the killing of 16 soldiers in a brazen attack in summer 2012.

The man, named Selmi Mohammed Musabah, also known as Abu Khaled, is suspected of being a leading member of militants behind the attack. He was killed just east of the city of el-Arish, the capital of North Sinai governorate.

The region has seen a rise of militant attacks against troops during the past three years of turmoil in Egypt, increasing after Morsi’s removal.

Copyright 2013 The Associated Press.