Dozens of people have been arrested following clashes outside a court in Alexandria where police officers were on trial for the killing of protesters during the January 25 Revolution.

Fighting erupted on Sunday between protesters and security forces after the trial judges announced they would step down just one day before they were due to deliver their verdict.

Hakim Abdel-Naim, a revolutionary socialist and student activist, told Ahram Online that security forces were conducting a crackdown on activists in downtown Alexandria following the clashes.

"Many people were arrested after the clashes. The interior ministry was arresting people randomly, dragging them out of cafes or even their cars," Abdel-Naim said.

Most of those arrested were under 18 and some were as young as 11, he added.

Dozens of those arrested cannot be located, Abdel-Naim said.

"It has been almost 12 hours and we still haven’t heard from those who were arrested. Nor have they been granted the right to inform their lawyers of their arrest. By law this is not an arrest, it's a kidnapping," he asserted.

At least nine more people were arrested on Sunday night after the court room was raided and some documents were set on fire, Abdel-Naim said. They will remain in police custody for four days pending investigations, he added.

Abdel-Naim said a protest in solidarity with the detainees would be held on Monday in front of Alexandria's general prosecution in the district of Al-Manshiya.

The clashes on Sunday left dozens injured, according to state-owned news agency MENA.

Tear gas and birdshot were used by security forces and some protesters have accused them of using live ammunition.

Two police cars were torched during the clashes.

Sunday's clashes represent the second such outbreak of violence outside Alexandria's criminal court building since the trial began.