Havana, Cuba (CNN) -- American government contractor Alan Gross went on trial in Cuba Friday in a case that appears to have derailed a tentative rapprochement between the long-estranged countries.
Cuba claims Gross -- a subcontractor for the U.S. Agency for International Development -- imported illegal satellite equipment to connect dissidents to the internet. He would face up to 20 years in prison if found guilty.
The United States says he was helping the Jewish community improve communications.
Gross on Friday was driven into the private drive of the courthouse, located in a converted mansion in a residential neighborhood of Havana. His wife, Judy, arrived on foot. Three U.S. officials also took seats in the courtroom as observers.
Gross was held for more than a year before Cuban authorities formally charged him with acts against the country's independence last month.
Judy Gross has appealed to Cuba to release him on humanitarian grounds.
"Alan's 88-year-old mother has just been diagnosed with lung cancer," she said in a written statement. "As I deal with that reality and our 26-year-old daughter's recovery from a double mastectomy, I can only continue to hope for Alan's return and beg the Cuban government to free Alan."
He "is an incredibly loving father," she noted in a video recording released shortly after her husband's arrest. "We've been married 40 years. His daughters miss him terribly."
In a December 2009 speech, Cuban President Raul Castro said Gross was illegally distributing "satellite communications equipment" to dissidents.
"The U.S. government has not renounced its goal of destroying the revolution," he said. "The enemy is as active as always. Proof of that is the detention, in the last few days, of an American citizen."
In a video that recently surfaced on the Web and that appears to be a leaked Cuban intelligence briefing, a speaker accuses Gross of using satellite phones to set up wi-fi hotspots.
The arrest put relations between the United States and Cuba back in a deep freeze despite initial signs of a thaw under President Barack Obama.
U.S. officials sharply criticized the charges against Gross after they were announced last month.
"We deplore the Cuban government's announcement that Cuban prosecutors intend to seek a 20-year sentence for Mr. Gross," said Gloria Berbena, public affairs officer for the U.S. diplomatic mission in Havana.
The White House also chimed in, claiming that Gross "has been unjustly detained and deprived of his liberty."
"Instead of releasing Mr. Gross, so he can come home to his wife and family, today's decision by Cuban authorities compounds the injustice suffered by a man helping to increase the free flow of information to, from and among people," then-White House spokesman Robert Gibbs said in a statement.
Secretary of State Hillary Clinton told reporters Friday that Gross had been "unjustly jailed for far too long." He needs to be able to leave Cuba and return home, she said. This is a matter "of great personal pain" to his family and concern to the U.S. government.
Foreign diplomats have speculated that Cuba will find Gross guilty, but could release him fairly quickly on humanitarian grounds.