A suicide bomber on foot blew himself up outside a compound for security contractors in southern Afghanistan on Wednesday, killing two Americans and five Afghans, officials and witnesses said. The bomber hit the men as they came out of the Kandahar compound of the USPI security company, said Rohullah Khan an official with the company. Three others were wounded, he said. The area where the attack happened is located opposite the Canadian Provincial Reconstruction Team inside Kandahar city. The blast was the sixth suicide attack in Kandahar province in the last nine days. Provincial police chief Asmatullah Alizai said that two foreigners, four Afghan policemen and a translator were killed.