Smoke bombs were thrown and protesters forced their way into buildings
Thirteen people have been arrested after violence erupted at a student demonstration, the University of Birmingham said.
It said smoke bombs and fireworks were thrown, doors smashed down and staff injured on its Edgbaston Campus.
The protest was against rising tuition fees and low staff wages.
Vice Chancellor David Eastwood described events as "disgraceful" and apologised to anyone affected by the "unacceptable behaviour".
The male and female protesters were arrested on suspicion of assaulting security guards, trespass and criminal damage, West Midlands Police said.
Several are from Birmingham, with others from Cambridge, Nottingham, Leicester, London, Leeds, Rugby and Buckinghamshire, the spokesman said.
Supporters of Defend Education Birmingham unfurled a banner on the university clock tower and occupied two buildings.
They claim about 100 students were contained, or "kettled", by police for four hours when arrests were made.
Kirsty Haigh, an activist from Edinburgh University, said: "What we saw from management and police was utterly disgraceful.
"Universities everywhere are losing the argument on staff exploitation and privatisation and the only argument we saw from them was brute force."
A spokeswoman for Birmingham University said they had "no choice" but to call in police.
She added: "The actions of Defend Education Birmingham, a group not affiliated to the Guild of Students or in any way representative of our student body, included defacing buildings and property, throwing smoke bombs and fireworks, smashing down doors, damaging buildings including Aston Webb and the Old Joe clock tower, and injuring staff."
Supt Lee Kendrick of West Midlands Police said the force "refuted" any suggestions of kettling.
He said: "Police were called to the site by the university as a result of demonstrators breaking into buildings, damaging property and assaulting staff.
Thirteen protesters were arrested after refusing to provide their names, West Midlands Police said
"The suspects were detained by police and required to give their details ahead of the pending criminal investigation - any that refused were arrested."
Dominic Drew, a University of Birmingham student, said he thought the protesters should "just grow up".
"It trashed the university, disrupting people's university education is not right," he said of the demonstration.
The University of Birmingham Guild of Students was not involved in the protest and said it did not condone the "extremely disappointing" behaviour.
The protest group said it expected strikes and student occupations to intensify in coming weeks.