"One of our police posts was attacked in Arghandab last night. At this point I can confirm that 11 policemen have been killed," Amanuallah Khan, the deputy provincial police chief, said on Monday.
Police vehicles and weapons were also seized by the attackers, Khan said.
He laid the blame for the raid on the "enemies of Afghanistan".
Kandahar province was where the Taliban rose to prominence in the early 1990s and is one of the worst hit regions in anti-government campaign led by the grouo since their removal from power.