The White House has called for election and UN human rights monitors in Zimbabwe to ensure an end to violence against opposition leaders and their supporters in a presidential run-off. Talking to reporters at Crawford, The White House spokesman Gordon Johndroe said Zimbabwean opposition leaders and their supporters must be able to freely campaign in the presidential runoff poll. Gordon Johndroe called for election and United Nations human rights monitors in the country to ensure free, fair and independent elections. Zimbabwe's opposition leader Morgan Tsvangirai has said he would return home despite the risk of more violence during polls.