Zimbabwe's main opposition party has denounced a planned delay in the country's presidential runoff, and says it wants regional leaders to discuss the crisis.

Tendai Biti (file)

Tendai Biti - secretary-general of the Movement for Democratic Change - insisted Thursday that the election be held by May 23, in line with laws that say a run-off must come within 21 days of the election results being announced.

Addressing reporters in South Africa, Biti called on the Southern Africa Development Community to hold an emergency summit and pressure Zimbabwe's government to cancel the postponement.

The electoral commission said Wednesday it will hold the runoff by July 31 - a full 90 days after the election results were released. MDC officials call the delay illegal.

The official results from the March 29 vote showed MDC candidate Morgan Tsvangirai beating President Robert Mugabe, but falling short of a majority needed to avoid a runoff.

The MDC disputed those results but has agreed to take part in the runoff. Mr. Tsvangirai, who has been outside Zimbabwe since shortly after the election, is expected to return soon to begin campaigning.