The head of Zimbabwe's opposition Movement for Democratic Change, Tendai Biti, has been arrested and will be charged with high treason, according to police sources. Peta Thornycroft reports for VOA from Harare Biti was arrested when he stepped off the plane from South Africa.

Biti predicted his arrest before he left Johannesburg, where he went shortly after Zimbabwe's March 29 elections. On his arrival in Harare, he was taken into custody by 10 plain clothesmen.

The police say he will be charged with high treason, which in Zimbabwe carries a death sentence.

Biti is a lawyer by profession and a senior partner in a leading Harare law firm. He was re-elected as a legislator in the March 29 elections.

National police spokesman Wayne Bvudzijena said Biti would be charged for allegedly publishing a document that is said to have contained details of a plot to fix the election outcome.

The state media said they had a secret document written by Biti, which it claimed showed how teachers employed by the Zimbabwe Election Commission had agreed to overstate the MDC's vote in return for payment. Scores of election officials were arrested and some face trial.

Bvudzijena said Biti would also face a separate charge of "communicating and publishing false information prejudicial to the state" after he proclaimed victory ahead of official results.

He was arrested on the same day th at many human-rights organizations were either forced to closed down or shut their doors when staff members fled for fear of arrest.

Most opposition members of parliament are in hiding or have fled to Botswana. About four are in detention, and several more are out on bail accused of political offenses, such as inciting violence.

MDC leader Morgan Tsvangirai also left Zimbabwe after the March 29 election for fear of persecution, but returned to Zimbabwe at the end of May to contest the June 27 runoff election.

A few observers from the Southern African Development Community have arrived in Zimbabwe to monitor the elections, but have not been deployed throughout the country.

The Bush administration has been pressing African countries and international organizations to increase election monitoring as the crucial runoff nears, and said it is ready to put up $7 million to support the effort.