A leading official of the Zimbabwean opposition Movement for Democratic Change (MDC) was Tuesday formally charged with treason.
MDC secretary general Welshman Ncube was formally charged in connection with an alleged plot to kill incumbent President Robert Mugabe, who is also candidate of the ruling Zimbabwe African National Union -- Patriotic Front (ZANU-PF).
Ncube, one of three top MDC officials, had previously been arrested in February, along with MDC chairman Morgan Tsvangirai and another party official, when police accused all three of treason.
According to the alleged plot, the MDC hired a Canadian company with security links to murder Mugabe ahead of the present presidential poll, to enable Tsvangirai assume power under the cover of the post-assassination confusion.
The party has since dismissed the allegations, even though the Canadian company has given Zimbabwean police what it claims to be video footage and other evidence of the plot.
The incident came as the counting of votes got under way in the country's presidential election amid increasing criticism of the way the poll was conducted.
The counting of votes started Tuesday morning with preliminary figures suggesting a turnout of nearly 70 percent in areas traditionally loyal to Mugabe, and just below 50 percent in Harare, which the MDC considers its stronghold.
Under Zimbabwe's first-past-the-post system, which was inherited from its former colonial power of Britain, the winner needs only one more vote than his closest rival.