Fiery explosions could be seen inside the university as riot officers entered before dawn Monday.

Police fired tear-gas barrages late Sunday at protesters outside the campus after an ultimatum to come out expired. The police had surrounded the university to prevent protesters from escaping as they moved in.

The protesters, numbering around 200 people, had assembled an arsenal of petrol bombs and bows and arrows to resist.

An officer from the media liaison team was stuck in the leg by an arrow around 2 p.m. and taken to police headquarters.

The protesters had also set fires on bridges leading to the university to keep police from advancing on their campus stronghold.

Orange flames extended the length of a footbridge over the roadway entrance to the Cross-Harbour tunnel.

Earlier Sunday, police had shut down access to the area and massed to surround the protesters, prompting some to retreat inside the campus while others remained outside to deter any advance.

Another fire was set on a bridge over the toll booths for the tunnel. Protesters have blocked access to the tunnel for days and set fires in the toll booths.