A suicide car bomber detonated his explosives near a hotel in southern Afghanistan, killing at least six people and wounding nearly two dozen Thursday, officials said.The blast in Kandahar happened as NATO and Afghan forces were preparing for a joint offensive against Taliban terrorists in the neighboring province of Helmand in a major bid to break the Taliban stranglehold on the south.The blast occurred in a busy commercial area near a major road that is frequently used by US officials and other dignitaries in Kandahar, the main commercial center of the south.But the six killed, including a child, were near the hotel, according to hospital official Mohammad Ibrahim. He said 18 people also were wounded.