Cuban prosecutors announced Friday that they will seek a 20-year prison term for U.S. government contractor Alan Gross, who was arrested more than a year ago for distributing satellite communication equipment to the island's Jewish community.

Despite emotional pleas by his wife for his release and tough talk by the Obama administration, prosecutors said they would charge Gross with "acts against the integrity and independence." Gross has been held in a Cuban jail cell since December 2009.

The detention of the 61-year-old Maryland resident has dampened attempts to improve relations between old adversaries. The announcement by Cuban state media on Friday via a government-run Web site will likely freeze further efforts by the Obama administration to soften its stance toward Cuba.

Arturo Valenzuela, assistant secretary of state for Western Hemisphere affairs, recently said it would be "very difficult to move to greater engagement in the context where they have continued to hold Alan Gross."

Gross, who lived in Potomac with his wife and has two daughters, was arrested while working to provide satellite-phone and computer gear to Cuban Jews to help them communicate with Jews abroad. It was part of a secretive American democracy-promotion program that grew during the George W. Bush administration, under the auspices of the Agency for International Development.

Cuban officials, including President Raul Castro, have suggested that Gross is a spy. U.S. diplomats have denied that, and sought to portray him as a luckless pawn in a geopolitical struggle.

The White House on Friday said it remained "deeply concerned" about Gross, adding that Cuba's latest decision "compounds the injustice suffered by a man helping to increase the free flow of information, to, from and among the Cuban people."

A lawyer for Gross's family urged Cuban authorities to free him immediately on time served.

"The charges announced today by the Cuban authorities against him demonstrate once again that Alan is caught in the middle of a long-standing political dispute between Cuba and the United States," said the lawyer, Peter J. Kahn. "Alan and his family should not have to pay the price for more than 50 years of turmoil in U.S.-Cuba relations."

In recent weeks, there had been some signs of warming. U.S. officials had traveled to the Communist-ruled island to discuss Gross's case. Last month, the Obama administration announced the broadest liberalization of travel to Cuba in a decade, making it easier for American students and groups to visit the country.

But the steep punishment being sought by Cuban prosecutors in the Gross case is likely to set relations back once again. U.S. officials had expected Gross would be accused of a crime but were hoping for a lesser charge.

Cuba officials have said that Gross, a subcontractor for Bethesda-based Development Alternatives, was clearly violating their laws when he tried to provide Jewish groups online access via satellite connections. Visitors who come to Cuba with satellite phones but no permit risk confiscation and arrest.

The announcement that Cuba would seek a maximum sentence for Gross came on the same day that Cuba said it would free two of the last 11 political prisoners who remained behind bars, in a deal to free dissidents brokered by the Catholic Church on the island.

Castro agreed to free 52 jailed dissidents. Most went to Spain.

Staff writers Tara Bahrampour and Mary Beth Sheridan contributed to this report.