THESSALONIKI, Greece (AP) — More than 5,000 university students and other protesters have gathered outside a courthouse in Greece’s second-largest city to rally against a new campus security law.

Tuesday’s protest in the northern city of Thessaloniki, a gathering banned under pandemic restrictions, was held in support of 31 people arrested Monday when a demonstration against the law turned violent.

Under the new measures approved by parliament this month, police can begin patrolling university grounds and make arrests. Police access to universities had previously been restricted for decades, causing a long-running political debate over on-campus freedoms.

The current conservative government argues that previous rules had allowed criminal activity and violent protests to occur on university grounds. But political opponents accuse the government of using the lockdown to sanction expanded police powers without a proper debate.

Some of the political controversy is rooted in the 1967-73 military dictatorship in Greece, when universities were an important source of political dissent. A bloody student-led revolt in 1973 helped topple the country's military regime.