Alan Gross, the US contractor jailed in Cuba on espionage charges, thanked a Washington-based Jewish group for trying to obtain his release, the group said in a statement Monday.
"It's very comforting to know I'm not forgotten, it helps to sustain me," said Gross, 63, according to a statement from the Jewish Community Relations Council of Greater Washington (JCRC).
The group said it spoke to Gross by phone for half an hour last week.
The JRCR is carrying out a series of activities seeking to create pressure for Gross's release that include weekly Monday vigils outside the Cuban interest section in the US capital.
Gross was arrested in December 2009 for distributing laptops and communications equipment to members of Cuba's small Jewish community under a US State Department contract. He was found guilty in March 2011 of "acts against the independence or territorial integrity" and sentenced to 15 years prison.
Gross said that personal letters he received from students at a Washington DC-area Jewish school "brought tears to my eyes and a smile to my face."
Cuba has refused Gross's requests for permission to visit his sick 90-year-old mother who is suffering from lung cancer in the United States.
"The cruelty to my mother is difficult to bear," Gross said in the phone call.
Nevertheless he described the Cuban people as "wonderful, friendly, creative, and patient."
Cuba has indicated that they would consider releasing Gross if the United States frees members of the Cuban Five espionage ring.
The five men were found guilty in 2001 of trying to infiltrate US military installations in South Florida and were given long prison terms, ranging from 15 years to life.
Cuba has acknowledged the five were intelligence agents, but says they were gathering information on "terrorist" plots by Cuban expatriates in Florida, not spying on the US government.
The contractor has always denied the charges against him, and Washington has continued to press Havana for his release.
The JCRC "calls upon the Cuban government to end its unconscionable incarceration of Alan immediately," the statement read.