A large group of pro-Palestine demonstrators took over Siemens Hall at Cal Poly Humboldt in Arcata, California, on Monday, eventually clashing with police in a tense moment captured on film.

When officers approached the group, one of the protesters escalated the situation by bashing a cop on the helmet with a plastic jug.

After a brief struggle, the policemen were called off and allowed the group to occupy the building.

See the full video of the demonstration below: