A Cuban exile who has spent nearly three years in U.S. custody without criminal charges has gone on a hunger strike.

Juan Emilio Aboy says he will not eat until he is released from a Miami, Florida immigration jail. 

Drinking only water to survive, Mr. Aboy claims to have lost nearly 16 kilograms since beginning the hunger strike several weeks ago. 

Federal investigators accuse Mr. Aboy of working as a courier for a network of Cuban government operatives in the 1990s.  They say he was also ordered to infiltrate the U.S. military's Southern Command, the command for Latin America and the Caribbean.

Mr. Aboy denies the accusations, and the government has never brought formal charges against the 44-year-old Cuban native.

Some information for this report provided by AP.