A man has been arrested after attacking several people with a baseball bat at Australian National University's Canberra campus.
Police said the 18-year-old Caucasian male, who is a student at ANU, stood up at the back of his statistics class just after 9am on Friday and approached the lecturer with the bat.
Four people were injured after attempting to reprehend the attacker.
Police said three women including the lecturer and one man received serious injuries and were taken to hospital.
ANU security arrived and restrained the attacker until police arrived and took him into custody.
Police have praised the students who intervened for their bravery. During the assault, one student grabbed the baseball bat from the attacker and fled, before later returning to the scene and passing the weapon to police.
The attacker is not known to police, however they said it was still too early to determine his motivation.