The United States has called for urgent UN Security Council talks on Zimbabwe because it said President Robert Mugabe had ignored international calls to end political violence ahead of a presidential election run-off.
Zimbabwean police arrested opposition leader Morgan Tsvangirai twice yesterday, making a total of four times in about a week. Tsvangirai's spokesman said the arrests were part of a harassment campaign in the run-up to the June 27 election.
Tendai Biti, secretary general of Tsvangirai's Movement for Democratic Change (MDC), was also arrested and would face a treason charge that could carry the death penalty, police said.
White House spokeswoman Dana Perino, accompanying President George W. Bush on a visit to Rome, criticised the "continued use of state-sponsored violence in Zimbabwe and the regime's actions, including unwarranted arrests of opposition figures".
"We believe the time has come for the United Nations Security Council to take up immediately the issue to prevent further deterioration of the region's humanitarian and security situation," Ms Perino said.
A group of prominent African leaders joined the international chorus for an end to political violence in Zimbabwe, once a regional bread basket but now in economic meltdown.
"It is crucial for the interests of both Zimbabwe and Africa that the upcoming elections are free and fair," former UN Secretary General Kofi Annan and 39 former African heads of state and civic leaders said in an open letter today.