An American diplomat died of his injuries after being shot by unknown gunmen in in the Sudanese capital Khartoum, the DPA reported from Khartoum and Nairobi on Tuesday. The attack occurred early Tuesday morning, and Sudan's interior ministry said the embassy car was fired on while it was driving in a residential neighbourhood in the capital, the BBC reported. It was unclear what motivated the shooting. "This afternoon, the American officer succumbed to his injuries and passed away," the US embassy in Khartoum said in a statement. We are working closely with local authorities to investigate the incident," it said. The envoy was an officer with the US Agency for International Development. His Sudanese driver was also killed in the attack, the BBC reported.