A US diplomat shot in Khartoum while riding in a car early Tuesday died of injuries sustained in the attack, which also killed the official's Sudanese driver, the US Embassy said. The shooting came a day after a joint African Union-United Nations force took over peacekeeping duties in Sudan's Darfur region. But it was not immediately known if the motive for the attack was political or a random crime. "This afternoon, the American officer succumbed to his injuries and passed away," said Walter Braunohler, the public affairs officer at the US Embassy in Khartoum. Braunohler said the diplomat, whose name was not released by the embassy, worked for the US Agency for International Development.