The U.S. aid contractor sentenced to 15 years in a Cuban prison after he was caught distributing communications gear on the Communist island testified here Friday at an appeal hearing before Cuba's supreme court, which is expected to issue its ruling in the coming days, official media said.

"Alan Phillip Gross ... outlined the criteria he considered pertinent and expressed gratitude for the chance to personally explain them before the judges of the People's Supreme Tribunal," according to a note on the government Web site Cubadebate.

Gross was represented at the hearing by Cuban public defender Nuris Piñeiro, while diplomats from the U.S. Interests Section in Havana observed the closed-door proceedings.

Now 61, Gross was arrested 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 island.

Early this year, Gross, a sub-contractor for the U.S. Agency for International Development, or USAID, was formally accused by the Cuban government of "acts against the independence and territorial integrity" of the country.

He was convicted in March and sentenced to 15 years behind bars.

The U.S. government has insisted from the beginning that Gross is innocent. Washington blasted his conviction as "unjust" and is demanding his "immediate and unconditional" release.

U.S. officials have categorically dismissed suggestions that Washington offer to trade five imprisoned Cuban spies for Gross.

The five Cubans were arrested in 1998 and convicted three years later by a federal jury in Miami.

A three-judge panel of the 11th U.S. Circuit Court of Appeals in Atlanta overturned the spies' convictions in 2005, citing the "prejudices" of Miami's anti-Castro Cubans.

But the full court later nixed the spies' bid for a new trial and reinstated the original convictions. In 2008, another three-judge panel of the 11th Circuit again refused to overturn the convictions.

Havana acknowledges that Gerardo Hernandez, Rene Gonzalez, Ramon Labañino, Antonio Guerrero and Fernando Gonzalez are intelligence agents, but says they were spying on Miami's Cuban exile community, not the U.S. government.

Hernandez, 45, is serving two life sentences, one for espionage and the other for his ostensible role in the 1996 downing by Cuban MiGs of two civilian airplanes belonging to the Miami-based exile group Brothers to the Rescue, four of whose members were killed in the incident over international waters.

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.