Fernando Gonzalez, one of five Cuban spies convicted by a Miami jury in 2001, was released Thursday from U.S. federal prison after serving more than 15 years.

Gonzalez, 50, who was being held at a prison in Safford, Arizona, was immediately taken into custody by immigration authorities and will be deported back to Cuba.

Another of the "Cuban Five," Chicago-born Rene Gonzalez (no relation to Fernando), was paroled in 2011 and allowed to return to Cuba last year after renouncing his U.S. citizenship.

The other three agents remain behind bars in the United States.

Fernando Gonzalez was originally sentenced to 19 years after being convicted of failing to register as a foreign agent and carrying false identification documents.

His sentence was subsequently trimmed to 17 years and prison officials granted him early release for good behavior.

The two Gonzalez men and their three colleagues - Gerardo Hernandez, Ramon Labañino and Antonio Guerrero - were arrested Sept. 12, 1998, and convicted three years later by a federal jury in Miami.

Hernandez is serving two life sentences for Cuba's downing of two small aircraft belonging to Miami-based exile group Brothers to the Rescue, which resulted in four deaths.

The Cuban Five insisted they were spying on Miami's Cuban exile community, not the U.S. government.

Cuba says the men were sent to Florida in the wake of several terror bombings in Havana allegedly masterminded by anti-Castro militant Luis Posada Carriles, a former CIA operative.

Havana has suggested an exchange of its spies for U.S. government subcontractor Alan Gross, who is serving a 15-year sentence in Cuba on a conviction for subversion.

The United States rejects talk of a swap, instead demanding that Cuba release Gross without conditions. EFE