Zimbabwe President Robert Mugabe is vowing that the country's opposition leader will never rule Zimbabwe and says he is prepared to fight to keep the opposition from taking power.

President Mugabe said Saturday that he would never accept the opposition Movement for Democratic Change (MDC) leading the country.

Opposition leader Morgan Tsvangirai told VOA the president's comments are very unfortunate and irresponsible. He said President Mugabe is not behaving like a statesman, but rather like a warlord. Mr. Tsvangirai also said the government's attempts to frustrate his campaign will not work. He said he is determined to continue on the presidential campaign trail until the run-off vote takes place on June 27.

The opposition leader was again detained by police Saturday for several hours as he campaigned. He has already been detained several times this month.

His party's second-ranking figure, Tendai Biti, is facing charges of treason, an offense punishable by death. He made his first court appearance Saturday in the capital, Harare.

Police say the treason charge against Biti stems from an MDC document about changing Zimbabwe's government. Authorities also accuse Biti of prematurely announcing the results of the March presidential election, which showed victory for Mr. Tsvangirai.  For doing so, police plan to charge Biti with spreading false information that is harmful to the state.

The MDC has accused President Mugabe's supporters of repeated attacks and intimidation ahead of the presidential run-off vote due in less than two weeks.  The coalition of opposition groups says more than 60 of its workers have been killed since the first round of the presidential election.