The Pentagon has said it had dispatched a surveillance aircraft and an Air Force search and rescue team to try to locate an Air France passenger jet believed to have crashed in the Atlantic Ocean.
The US military plane departed the air base used by the US Southern Command Air Base in Comalapa, El Salvador at about 6:10 pm (2210 GMT), the Pentagon said on Monday.
Earlier in the day, French Defence Minister Herve Morin asked for US help in locating the disappeared passenger plane, during a conversation with his American counterpart Defence Secretary Robert Gates.
Brazil's air force deployed aircraft with radar and infrared technology during an overnight search for the missing plane, that was carrying 228 people when it disappeared over the Atlantic.
Air France flight AF 447 disappeared early Monday, four hours into its 11-hour flight from Rio de Janeiro to Paris. More than half the 216 passengers on board were either Brazilian or French.