An explosion struck a bus carrying government employees during rush hour traffic in the Afghan capital of Kabul on Wednesday, wounding four people, police and witnesses said.
The blast occurred just before 5 p.m. (1230 GMT) on a major road near a university and an old parliament building.
The target appeared to be a bus carrying employees of the Ministry of Mining and Petroleum, said Sediq Seqqi, a spokesman for the Interior Ministry.
Among the wounded were three men and one woman, officials said.