No one immediately took responsibility but Saifi blamed the Islamic State group, saying they regularly plant roadside bombs to target Afghan officials and security forces.
IS has a strong presence in Nangarhar, where Afghan and U.S. support troops have targeted their outposts
Elsewhere in Afghanistan, a van hit a roadside mine in northeaster Kunar province, killing three people and wounding 16 others Wednesday, said Abdul Ghani Musamim, spokesman for the provincial governor.
Afghanistan is one of the world’s heaviest mined countries.