Morgan Tsvangirai 's lawyer arrested.

Innocent Chagonda was arrested on Thursday for simply demanding the release of a helicopter hired by Morgan Tsvangirai for his presidential campaign, the opposition Movement for Democratic Change (MDC) and another lawyer said.

The helicopter had been confiscated by police and the pilot, a South African national, was detained on March 25 for alleged fraud and immigration transgressions. He spent nine days behind bars before being freed.

"As a party we feel this is a sustained effort on the part of the authorities against people who assist the MDC," spokesman Nelson Chamisa said.

"This is an onslaught which is not only happening in the rural areas, but even in the civil service as people who are perceived MDC supporters are being intimidated."

Zimbabwe is still awaiting the result of the presidential election on March 29. Mr Tsvangirai claims outright victory, but Mr Mugabe's ruling Zimbabwe African National Union - Patriotic Front (ZANU-PF) says there must be a run-off.

The opposition on Thursday ruled out Mr Tsvangirai's participation in any second-round vote, accusing Mr Mugabe and his regime of having launched a campaign of intimidation that would affect the true democratic result.