An American tourist and her driver were kidnapped by gunmen in Uganda, local officials said.Police and the national tourist board identified the American woman as Kimberly Sue. Investigators said the driver’s name was Jean Paul.The assailants used one of the victims’ cellphones to call authorities and demand $500,000 for their release, police said, adding that they “strongly believe this ransom is the reason behind the kidnap.”Four kidnappers abducted the American and the driver, taking their keys but leaving the vehicle behind, according to police. The others in the vehicle escaped unharmed and later contacted authorities. The government earlier said that four people had escaped the incident.