U.S. citizen Alan Phillip Gross went on trial Friday in Havana on charges of spying and supporting anti-Castro groups on the island.

Prosecutors are asking for a 20-year sentence on charges of "acts against the independence or territorial integrity of the Cuban state," Cuban official media said.

The 61-year-old U.S. contractor from "Development Associates International" was arrested on Dec. 3, 2009 at the Havana airport after delivering satellite communication equipment to an anti-Castro Cuban Jewish organization, which Washington said was to help them communicate with the outside world.

However, leaders of Jewish groups in Cuba denied they have any contact with Gross.

Adela Dworin, vice president of the Jewish Patronage, said last December that she had never met Gross.

Mayra Levy, president of the Hebrew Sephardic Center of Cuba, also said she had never met Gross nor visited that American institution.

Gross has been detained at a military hospital in Havana for a whole year without filing formal charges.

His wife Judy Gross wrote to Cuban leader Raul Castro last August, saying she regretted her husband's work in Cuba.

Meanwhile, she criticized the White House for not doing enough and described her husband as "a victim caught in the crossfire between the two foes of the old Cold War."

The U.S. State Department has recently dismissed an alleged plan to exchange Gross for one of the five Cubans imprisoned in the United States since 1998 on charges of espionage.

On Dec. 20, Castro cited the Grosscase in parliament as an example of the United States' continuing "its aggressive policy against the island."