Ismail Khan, who is also running as vice president for one of the candidates in the April 5 presidential election, was attacked after mid-day prayers, said police spokesman Abdul Raouf Ahmadi.
Khan was coming out of the mosque in Herat city, the provincial capital, when the bomber set off his explosives. No one except the would-be suicide bomber was killed in the explosion, said Ahmadi. Khan could not be reached for comment.
In 2010, President Hamid Karzai had wanted to keep Khan - a Tajik who was a prominent warlord during the civil war of the 1990s and who retains considerable local power among his minority - in his administration, but the nomination was narrowly defeated. Critics said keeping Khan would have proven Karzai remained beholden to regional power brokers at the expense of the country's national interests.
Both Sayyaf and Khan were known as warlords during Afghanistan's civil war from 1992 until the Taliban takeover in 1996, fighting on the side of the Northern Alliance against the Taliban. Previously, both also actively participated in the war against the Soviet occupation.
