One of five Cuban agents jailed in the United States on spy charges has been released from prison after serving 13 years of a 15-year sentence.

Fifty-five-year-old Rene Gonzalez walked out of a Florida prison early Friday, but must remain in the United States for the next three years on probation. Gonzalez's attorney, Philip Horowitz, did not provide details as to where his client was headed. Horowitz has said he will make a renewed request for Gonzalez to be allowed to return to Cuba.

Gonzalez, part of the so-called “Cuban Five” espionage ring, was arrested in 1998. He and the other four agents were convicted in 2001 and sentenced to lengthy prison terms for being part of the ring that infiltrated exile groups in Florida. Cuba's government, which has hailed the five men as heroes, has said they were monitoring exile groups to protect the island from attacks.

Cuba has demanded that Gonzalez, who was born in Chicago, Illinois, be returned to the island.