KANDAHAR - Unidentified gunmen in southern Afghanistan stopped two buses traveling to the capital, Kabul, and seized around 30 people belonging to the ethnic Hazara minority, a bus company official said on Tuesday.The passengers were forced to leave the buses late on Monday night, after producing documents that showed they belonged to the Shi'ite minority group."Our drivers stopped for the gunmen because they were in army uniform. They asked for documents," Nasir Ahmad, one of the bus company's managers, said in the southern city of Kandahar."According to other passengers, most of the people abducted were Hazaras."The Taliban, now leading an increasingly violent insurgency against the government and its foreign backers, did not immediately claim responsibility but said they were investigating.The fate of the missing passengers was unknown, said Ghulum Jilani Sakhi, the deputy police chief of Zabul province, where Monday's abduction took place."We are investigating where these people have been taken," he added.