Updated at 2:27 p.m. ET
HAVANA - Cuba's highest court upheld a U.S. government subcontractor's 15-year prison sentence for crimes against the state on Friday, ending the legal side of a case that has chilled already-icy relations between Washington and Havana.
The ruling means 62-year-old Alan Gross, a Maryland native who has been behind bars for more than a year and a half, has no further judicial recourse to appeal his sentence. It leaves him, his family and U.S. officials hoping instead for a release on humanitarian grounds.
Gross, who has been behind bars since his arrest in December 2009, was found guilty in March of bringing satellite and other communication equipment into the country illegally. He has acknowledged he was working on a USAID-funded democracy program, but says he meant no harm to the government and was trying to help the island's tiny Jewish community.
On Friday, the Supreme Court "issued a definitive resolution denying the appeal filed by the U.S. citizen Alan Phillip Gross and his lawyer against the sentence issued by the People's Provincial Tribunal of Havana," said a note published on state-run website Cubadebate.
During the initial trial, the court found, "it was demonstrated that (Gross) illegally introduced telecommunications equipment in Cuba to create internal networks as part of a program of the government of the United States that aimed to promote destabilizing actions in the country and subvert Cuban constitutional order."
Prominent Jewish leaders in Havana have denied working with Gross.
"While we are not surprised, we are extremely disappointed with today's ruling, which marks the end of Alan's legal process in Cuba," Gross' U.S. lawyer, Peter J. Kahn, said in a statement. "The family is heartbroken by today's decision, but remains hopeful that there continues to be room for a diplomatic resolution of this matter."
The Gross case has been a stumbling block to any warmer relations between the Cold War rivals. U.S. officials say ties cannot improve while he remains in prison. A spokeswoman at the U.S. Interest Section in Havana said diplomats were still considering the ruling and were not ready to comment.
U.S. officials have said they did not expect the court to throw out Gross' conviction, but have held out hope that the end of the legal process might clear the way for his release on humanitarian grounds. Gross has lost 100 pounds (45 kilograms) in jail by his own estimation, and several family members in the United States have serious illnesses.
Cuban officials, meanwhile, have said privately they are sympathetic to humanitarian appeals, but would not consider them until the Supreme Court ruled.
"Entering his 21st month in a Cuban prison, Alan and the entire Gross family have paid an enormous personal price in the long-standing political feud between Cuba and the United States," Kahn's statement continued. "Now, more than ever, we call upon the two countries to resolve their dispute over Alan's activities diplomatically, and request that President Raul Castro release Alan immediately on humanitarian grounds."
Gross' arrest also caused soul-searching in Washington over the democracy programs, which are passionately supported by several Cuban-American politicians.
Senate Foreign Relations Committee Chairman John Kerry put a hold on funding this spring, arguing that the programs don't work and have in fact harmed U.S. interests.
"There is no evidence ... that the democracy promotion programs, which have cost the U.S. taxpayer more than $150 million so far, are helping the Cuban people," Kerry said at the time. "Nor have they achieved much more than provoking the Cuban government to arrest a U.S. government contractor."
Kerry recently lifted the hold after getting assurances from USAID and the State Department about oversight. And earlier this week, Sen. Patrick Leahy ended a similar hold, freeing the Obama administration to spend $20 million on the programs.
That prompted an angry response from Cuban officials, who chided the U.S. government for finding the money to fund "subversion" on the island even as it neared the brink of "bankruptcy," referring to the debt-ceiling standoff.
Sen. Marco Rubio, a Cuban-American Republican from Florida, issued a statement calling the ruling and Gross' detention a human rights violation.
"Mr. Gross is simply a humanitarian who was seeking to help the Jewish community in Cuba access the Internet," Rubio said. "The Castro regime's cowardly fear of what would happen if Cuban citizens have access to uncensored information does not justify this man's incarceration at all, much less for 15 years."