WASHINGTON: US President Barack Obama returned toWashington from Colombia Sunday after aSummit of the Americas over shadowed by a sex scandal involving Secret Service agents and military personnel.

Air Force One carrying the president and his aides landed at Andrews Air Force Base outsideWashingtonat11:56 pm(0356 GMT Monday).

The gathering in the Colombian resort city of Cartagenaended with regional leaders failing to agree onCuba's inclusion at future summits, in the face of Obama's opposition.

The trip marked theUSpresident's first visit toColombia.

No final statement was issued at summit's end given the dispute overCuba.

Obama justified his position in a post-summit press conference, sayingCubahad "not yet moved to democracy."