Zimbabwe's opposition presidential candidate has resumed campaigning the morning after spending nine hours in police detention in the country's second main city. Morgan Tsvangirai's party said in a statement Thursday that he had left Bulawayo to continue his campaign. It says he is "undeterred" by the detention and accuses President Robert Mugabe's government of trying to steal the June 27 presidential runoff. According to his party, police released Tsvangirai late Wednesday after charging him with "attracting a large number of people." Police have broad powers to restrict gatherings in Zimbabwe.