Zimbabwe's students are the target of a government attempt to clamp down on sectors of society that it sees as supporters of the political opposition, following Robert Mugabe's victory in this month's disputed presidential election.
Students returning to classes after a summer holiday extended over the presidential polling days were greeted by riot police and the arrest of three of their leaders.
The leaders were arrested at midnight on March 19 for allegedly helping the Zimbabwe Congress of Trade Unions and the Movement for Democratic Change (MDC) to organise a national work stay-away for the following day.
They are among 30 student activists suspended by the University of Zimbabwe last year. Many have had their suspensions renewed this year, banning them from campus and from pursuing their studies.
Philip Pasirayi, Zimbabwe National Students' Union information and publicity secretary, Madock Chivasa, treasurer of the Students'
Representative Council, and Eddington Shayanowako, of the Students'
Representative Assembly, were released on condition that they did not attend or address political meetings or walk in groups of more than five.
Students are being targeted, along with trade unionists and supporters of the MDC, for arrest and harassment by the security forces and paramilitary youth and "war veteran" militia angry at the challenge to Mr Mugabe.
Thousands of MDC supporters have been arrested and harassed and ten killed, reportedly by supporters of the ruling Zanu PF party, since the poll started two weeks ago.
The independent Daily News reported university spokesperson Elizabeth Karonga as confirming the arrests and the presence of riot police on campus. She said the students "were picked up by our security officers and handed to the Avondale police" after being found on campus in breach of their terms of suspension. Ms Karonga said: "UZ is a public place and the police are policing it like any other public place."
SRA vice-chairman Saki Otto said his colleagues were told by police that they had been picked up for helping to organise protests against the election.