Afghan television is set to broadcast a presidential debate, even as President Hamid Karzai says he is boycotting the event and one of the scheduled participants threatens to withdraw.

Mr. Karzai was due to appear Thursday night with his top two challengers, former Foreign Minister Abdullah Abdullah and former Finance Minister Ashrag Ghani.
But late Wednesday, Mr. Karzai's campaign staff said the president would not participate because there was not enough time to prepare for it.  The campaign also accused the debate's organizers, popular television station Tolo, of bias against the president.

Aides to Mr. Karzai say he will only participate if the debate airs on all Afghan television stations and more of the country's 41 candidates are invited.

Following Mr. Karzai's withdrawal, an aide to Abdullah said the former foreign minister might not participate.

The debate's producers are expected to include an empty lectern on the set where Mr. Karzai would have been.

Forty-one candidates, including two women, are competing for the country's highest post in the August 20 presidential election.

Mr. Karzai is seeking a second term in office, with current Vice President Karim Khalili and former Vice President Mohammad Qasim Fahim as his two running mates. 

Mr. Karzai has led Afghanistan since the U.S.-backed invasion.  He was elected to office in 2004.

A worsening Taliban insurgency in the country and charges of government corruption have weakened Mr. Karzai's image at home and abroad.  But so far, a strong challenger to his re-election bid has not emerged.

Earlier this month, 4,000 U.S. Marines, along with British and Afghan troops, launched a major anti-Taliban offensive in Helmand aimed at ensuring security ahead of the election. 

Some information for this report was provided by AFP.