Zimbabwe's Prime Minister Calls Election a 'Huge Farce'
Observer group claims up to a million people were prevented from casting ballots
Zimbabwe's presidential election was a "huge farce", PM Morgan Tsvangirai has said, alleging vote-rigging by rival President Robert Mugabe's camp.
At a news conference, Mr Tsvangirai said that Wednesday's poll was "null and void".
The largest observer group earlier said up to a million people were prevented from voting.