A blast aimed at a convoy of U.S. troops killed an Afghan civilian and wounded five others on Monday in the eastern province of Nangarhar, a government spokesman said. There was no immediate reports of casualties among U.S. troops from the blast, south of the city of Jalalabad. Interior Ministry spokesman Yousuf Stanezai said the explosion was apparently caused by a bomb attached to a bicycle which went off as the convoy was passing.Nangarhar's deputy governor Mohammad Asef blamed the Taliban guerrillas and said the bomb could have been triggered by remote control. Taliban officials could not be reached for comment, but insurgents from the ousted Islamic movement have been behind attacks this year in which more than 1,100 people have died. Most of those killed have been militants, but the toll has included more than 50 U.S. soldiers, the bloodiest period for U.S. forces in Afghanistan since they overthrew the Taliban in late 2001.