He is now serving a 15-year prison sentence. Gross says he was only trying to provide Internet service to Cuba's small Jewish community. Cuba says the multimillion-dollar programs are an effort by Washington to undermine the government, and has noted that Gross was carrying sophisticated communications equipment.
Gross' lawyer has for months said his client's health is declining, and he and Gross' wife have called on the Cuban government to let Gross be examined by a doctor of their choice.
Gross' wife, Judy, was traveling to West Palm Beach, Florida, on Sunday for a rally in support of her husband's release. The rally was scheduled outside a performance of the National Symphony Orchestra of Cuba, which is currently making its first U.S. tour.
Also on Sunday, Gross' lawyer made public a letter addressed to Cuban President Raul Castro and signed by more than 500 rabbis. The letter urges Castro to release Gross, who is Jewish, on humanitarian grounds.
Dec. 3 will mark three years that Gross has been held in Cuba.
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