After Biti's arrest, Morgan Tsvangirai, the MDC presidential candidate, was detained for the third time in little more than a week, The New York Times reported. He was picked up with 20 companions on a campaign trip and held for two hours.

Biti, who had been in South Africa for two months, could face the death penalty. He was met by police at Harare Airport.

Wayne Bvudzijena, a police spokesman, said that Biti falsely said that Tsvangirai had won the March 29 presidential election. The official results, released weeks after the vote, said that Tsvangirai outpolled President Robert Mugabe without winning the 50 percent majority needed to avoid a runoff.

Biti also allegedly published a document detailing plans for changing the government, the spokesman said.

Bvudzijena called the MDC "mischievous" for claiming Tsvangirai was detained.

"He should expect just like any other citizen to be stopped at a roadblock, which have been there for time immemorial, and they don't amount to detention," he said.