MIAMI -

An American contractor who has been imprisoned in a Cuba for more than four years is on a hunger strike, according to his lawyer.

Alan Gross, 64, said he began fasting last Thursday to protest what he described as the inaction by both the U.S. and Cuban governments to secure his release.

Cuban authorities arrested Gross in 2009 for importing and distributing communications equipment for the Jewish community there. At the time, Gross was working under a program funded by the U.S. Agency for International Development to improve communication on the island. He was sentenced to 15 years for crimes against the Cuban state.

His attorney said he decided to take the extreme measure after the Associated Press reported on a secret program run by the U.S. government to stir unrest on the island. The program, dubbed the "Cuban Twitter" by officials who ran it from 2009 to 2012, was also run by USAID and initiated after Gross was imprisoned.

Gross said in a statement that he was frustrated by the continued lack of effort by the U.S. government to orchestrate his release.

"I am fasting to object to mistruths, deceptions and inaction by both governments, not only regarding their shared responsibility for my arbitrary detention, but also because of the lack of any reasonable or valid effort to resolve this shameful ordeal," Gross said in a statement released by his attorney. "Once again, I am calling on President (Barack) Obama to get personally involved in ending this stand-off so that I can return home to my wife and daughters."

USAID's top official, Rajiv Shah, was scheduled to testify Tuesday morning before a Senate subcommittee.