HAVANA (CBSMiami/AP) —  The Cuban government expressed concern Wednesday over a jailed U.S. government subcontractor on hunger strike since last week.

Alan Gross, 64, is on hunger strike to protest both Havana’s and Washington’s handling of his case.

READ MORE: Appeals Court Says Florida Tech Law Violates First Amendment

Josefina Vidal, the Cuban Foreign Ministry’s top official for U.S. affairs, said in a statement that Gross, from Maryland, is in good physical health. He has been serving his 15-year sentence at a military hospital in Havana.

“The Cuban government reiterates its willingness to seek, together with the U.S. government, a solution to Mr. Gross’ case … that takes into account the humanitarian concerns of Cuba related to the case of the three Cubans from the group of the Five,” her statement read.

The “Cuban Five” are intelligence agents sentenced to long prison terms in the United States. Two have completed their sentences, and three are still behind bars.

They were convicted on charges including conspiracy and failure to register as foreign agents, but Cuba calls them heroes who were trying to foil terror plots against the island by militant exile groups.

In the past, U.S. officials have ruled out swapping the Cubans for Gross and said the cases are not comparable.

Gross was arrested in December 2009 after he was caught setting up Internet networks for Cuba’s small Jewish community as part of a program funded by the U.S. Agency for International Development (USAID).

Cuba considers such programs an affront to its sovereignty and sentenced him to 15 years for crimes against the state. He maintains that his activities never posed any threat to the Cuban government.

On Tuesday, Gross’ U.S. lawyer, Scott Gilbert, said Gross had eaten his last solid meal the night of April 2, though he continues to drink water. He said Gross intended to maintain the hunger strike “as long as it takes.”

READ MORE: Site Of Surfside Condo Collapse To Be Sold To Dubai Developer

“I am fasting to object to mistruths, deceptions, and inaction by both governments, not only regarding their shared responsibility for my arbitrary detention, but also because of the lack of any reasonable or valid effort to resolve this shameful ordeal,” Gross said in a statement released through the lawyer.

His protest followed an AP investigation that revealed a separate USAID program to secretly create a text messaging-based social network in Cuba with the goal of stirring unrest. The network, called ZunZuneo, was publicly launched shortly after Gross’ arrest.

Gilbert called it the “final straw” that prompted Gross’ hunger strike.

Vidal’s brief statement did not offer any details about the strike, saying simply that officials “have learned with concern” about Gross’ protest.

She reiterated Havana’s assertion that Gross broke Cuban law “by implementing a subversive program financed by the U.S. government.”

On Capitol Hill Thursday, the head of USAID, Rajiv Shah, gave testimony on the “Cuban Twitter” known as ZunZuneo at a Senate Foreign Relations Committee hearing.

U.S. Senator Marco Rubio, who is a member of the committee, told lawmakers the program was designed to help Cubans communicate on the island and speak freely.

“When do we start the program again so people in Cuba can speak freely to the world and to each other about the reality of Cuban life..and about anything else they want,” asked Rubio.

MORE NEWS: Report: Three Americans Died Of Carbon Monoxide Poisoning At Bahamas Resort

Shah has denied that the “Cuban Twitter” program was meant to stir unrest on the island.