Relatives of a leading member of the opposition in Belarus have expressed concern for his safety.
Alexander Kozulin was arrested in the capital, Minsk, yesterday during protests against the outcome of the recent Presidential Election
The current holder of the EU Presidency, Austria, has demanded the immediate release of Mr Kozulin and expressed serious concern at the politician's detention.
Mr Kozulin was arrested after leading several hundred opposition supporters on a march to the main detention centre in the capital Minsk where it is thought hundreds of student demonstrators are being held.
The Belarus Interior Minister said Mr Kozulin was detained because he had called on people to attack the state.
Demonstrations have continued in recent days over the victory of President Alexander Lukashenko in a disputed 19 March poll.
The EU and US have criticised the election, which they said was neither free nor fair, and have vowed to impose sanctions.
