Two U.S. politicians are demanding Beyonce and Jay Z face an investigation over their vacation in Cuba.

Republican Congress Representatives Ileana Ros-Lehtinen and Mario Diaz-Balart have sent a joint letter to America's Treasury Department demanding information about whether the couple's travel plans were approved by the U.S. government.

The stars jetted to the Caribbean nation to mark their recent wedding anniversary, and pictures of the couple's holiday have since appeared online. American citizens are banned from visiting Cuba for tourism purposes and need to obtain a special travel licence from the American government to journey there, and the politicians are outraged about the high-profile couple's visit.

The letter demands "information regarding the type of licence that Beyonce and Jay Z received, for what purpose, and who approved such travel", adding, "The restrictions on tourism travel are common-sense measures meant to prevent U.S. dollars from supporting a murderous regime that opposes U.S. security interests at every turn and which ruthlessly suppresses the most basic liberties of speech, assembly and belief... Despite the clear prohibition against tourism in Cuba, numerous press reports described the couple's trip as tourism."

The couple's outing has previously enraged pro-democracy campaigners, who called the trip "extremely insensitive" in light of alleged human rights violations in Cuba.

If Beyonce and Jay Z travelled to Cuba without obtaining a licence from the U.S. government, they could be hit with a fine.