Afghan president's elder brother says he quit the April 5 presidential race to rally undecided countrymen in favor of a moderate candidate, the country's former foreign minister.

Qayyum Karzai says he believes most of Afghan voters are undecided and could be persuaded to back the moderate runner, Zalmai Rassoul.

The elder Karzai spoke in an interview on Friday with The Associated Press, one day after bowing out of the presidential race.

He says the undecided voters represent a "huge, huge" chunk of votes. Karzai says he backs Rassoul because he has the temperament and the moderate vision to steer Afghanistan through a "dignified transition."

Karzai's decision followed days of speculation and backdoor meetings.

Hamid Karzai, who has served two terms, is not eligible to run under Afghanistan's constitution.