A video showed a mob stopping and kicking her car and blocking her when she tried to escape on foot.

Comments on Brazilian websites pointed out the irony of the hatred directed at Arruda by fellow students in a nation obsessed with physical beauty and said the university's actions were unfair.

"Pure hypocrisy ... once February and the Carnival comes round everyone will be naked and no one will find it abnormal," said one comment posted by a reader on the O Globo news website.

The university said it had also suspended a number of students identified by video footage and witness accounts of taking part in the violence.

The university's legal adviser said Ms Arruda had been expelled for "gestures" and "attitudes" she had manifested rather than because of her short outfits. He would not give details.