Gunmen in Papua New Guinea burnt vehicles and evaded arrest after clashing with a team of 60 police at the University of PNG last night.
Police say they fired warning shots and used tear gas at the campus in Port Moresby to disperse a group of students and supporters, some of whom were armed with pistols.
Inspector Reuben Giusu of the Boroko police says the troublemakers scaled the university's two metre high fence with razor wire to burn two of the institute's four-wheel drive vehicles.
Inspector Giusu says no serious injuries were sustained during the four-hour clash, which ended without a single arrest.
"Of course it's disappointing for the police and the university as well, that brings the total number of vehicles to four, it's a big loss to the university. And it's a pity we could not make an arrest."
Students have been boycotting classes over the past fortnight to protest against the university's new grading system.