The wife of U.S. aid contractor Alan Gross, who is serving a lengthy prison sentence in Cuba on subversion charges, on Monday asked for President Barack Obama's intercession in the case.

"I spoke with Alan two days ago. Never have I heard him more hopeless and depressed," Judy Gross said during a protest outside the Cuban Interests Section in Washington.

Accompanied by a score of supporters from the Jewish Community Relations Council of Greater Washington, she called on Americans to write letters to newspapers and politicians, including Obama, urging action on behalf of her husband.

Gross, now 62, was arrested in Havana on Dec. 3, 2009, in possession of satellite communications equipment he said he was planning to distribute among Cuba's Jewish community.

Havana says he was illegally aiding dissidents and inciting subversion on the Communist-ruled island. In August, Cuba's highest court upheld the 15-year jail sentence imposed on Gross in March.

Judy Gross asked for increased pressure on Congress and Obama to obtain the release of her husband on humanitarian grounds, on the eve of the second anniversary of his arrest and imprisonment.

"Please join us in the effort to keep Alan's case top-of-mind with policymakers," she said Monday. "Tell everyone you know about Alan."

A Washington-area rabbi who visited Alan Gross in Havana said earlier this month that the Maryland native wants to be swapped for five Cuban spies held in the United States.

Gross expressed "anger and frustration" about his situation, Rabbi David Shneyer said in a message to his congregation in Bethesda, Maryland.

He said he spent nearly two hours with Gross.

"Having learned about the recent swap of (Israeli soldier) Gilad Shalit for more than 1,000 imprisoned Palestinians, (Gross) felt that the U.S. and Cuba could do the same for him and the 'Cuban Five,'" Shneyer said.

The five - Gerardo Hernandez, Rene Gonzalez, Ramon Labañino, Antonio Guerrero and Fernando Gonzalez - were arrested in 1998 and convicted three years later by a federal jury in Miami.

Though one of the group, Rene Gonzalez, completed his custodial sentence in October and was released, he has not been permitted to go home, as the federal courts say he must serve his three-year probation on U.S. soil.

Press accounts said Havana rejected a U.S. proposal to allow Rene Gonzalez to return to Cuba now in exchange for Gross' freedom, countering with a demand for the release of the four spies who remain in prison.

While acknowledging that the five are intelligence agents, Havana insists they were spying on Miami's Cuban exile community, not the U.S. government.

Cuba says the men were sent to Florida in the wake of several terror bombings in Havana allegedly masterminded by anti-Castro militant Luis Posada Carriles, a former CIA operative.