Former New Mexico governor Bill Richardson is traveling to Cuba to seek the release of U.S. contractor Alan Gross, who is serving 15 years in prison for crimes against the communist state.

The State Department said Wednesday it was “aware” of Richardson's trip and that it supports the former governor's efforts to obtain Gross's release. But spokesperson Victoria Nuland said Richardson was traveling as a private citizen.

Richardson traveled to Cuba a year ago on a similar trip, meeting with Cuban Foreign Minister Bruno Rodriguez to discuss Gross's imprisonment. At that time, Richardson said he was told the case against Gross was at a very sensitive investigatory and legal point.

Last month, Cuba's Supreme Court rejected an appeal from Gross, who was arrested by Cuban authorities in December 2009 for bringing communications equipment into the country.

At the time of his arrest, Gross was working for a private firm that contracted with the U.S. Agency for International Development. He was accused of distributing Internet equipment and satellite phones to Cuban dissident groups. Gross said he was trying to improve Internet access for the island's small Jewish community and that his actions were not intended to be a threat against Cuba's government.

The White House has described the sentencing of Gross as “another injustice.”

His family has appealed on humanitarian grounds for the 62-year-old contractor to be returned home.

The United States and Cuba do not have formal diplomatic relations, only interests sections that are technically part of the Swiss embassies in each other's capitals.