"There was some sort of fight in the toiletes and there was blood on his face and something. Then some guys turned up with a baseball bat, knife and spanner and started to attack the guy," student Heiðar Már Hildarson says.
He says he and other students were gripped by fear when the incident grew: "At first, I thought it was something small but then it became so big that I was afraid something [terrible] would happen."
The above mobile phone footage shows part of the attack and is being widely shared on social media.
