Two U.S. senators expressed optimism Tuesday that Cuba will free imprisoned American government contractor Alan Gross.

Sens. Jeff Flake, a Republican from Arizona, and Tom Udall, a Democrat from New Mexico, said they met with Gross for about two hours during a trip that included meetings with Cuban officials.

Gross was detained in December 2009 while working to set up Internet access as a subcontractor for the U.S. Agency for International Development. He was tried and sentenced to 15 years in prison. Gross' family has said he has threatened to commit suicide if he is not released by his birthday next May.

Asked about the possibility of Gross going free, Flake said: "I do feel we're closer there, one because what Alan Gross has said himself, this is going to end one way or another."

Both two senators added, though, that Cuban officials gave no indication any development was imminent.

Flake also cited as cause for optimism a report by The Associated Press on Monday that USAID is preparing internal rules that would effectively end risky undercover work in hostile countries.

The new policy follows an AP investigation this year into work by the development agency, which set up a Twitter-like social network in Cuba and secretly sought to recruit a new generation of dissidents on the island while hiding ties to the U.S. government. The AP found USAID and its contractor concealed their involvement in the programs by setting up a front company, routing money through Cayman Islands bank transactions and fashioning elaborate cover stories.

"There's been a realization and a statement that there won't be covert programs run out of AID anymore and that's a good thing," said Flake, who is a longtime advocate of loosening the U.S. trade embargo on Cuba. "It's not just a source of tension between countries; it puts Americans in danger and it really cheapens AID's mission around the world, in my view."

USAID has denied the Cuba programs constituted covert action.

Cuba has said repeatedly it wants to negotiate with the U.S. over the fate of Gross as well as three Cuban agents who are imprisoned in the U.S. on charges including espionage. Cuba argues they were only keeping tabs on militant exile groups blamed for terror attacks on the island.