US President Barack Obama and British Prime Minister David Cameron(L) listen to national anthems during a welcome ceremony March 14, 2012 on the South Lawn of the White House in Washington, DC. AFP PHOTO/Mandel NGAN [Obama: no se prevén cambios “repentinos” en retiro de tropas de Afganistán]

US President Barack Obama and British Prime Minister David Cameron(L) listen to national anthems during a welcome ceremony March 14, 2012 on the South Lawn of the White House in Washington, DC. AFP PHOTO/Mandel NGAN

US President Barack Obama and British Prime Minister David Cameron(L) listen to national anthems during a welcome ceremony March 14, 2012 on the South Lawn of the White House in Washington, DC. AFP PHOTO/Mandel NGAN