An overseas Tibetan spokesman says China has released noted political prisoner Jigme Gyatso after 17 years in prison on charges of endangering national security and separatism.

The 52-year-old former monk has returned to his hometown in an ethnic Tibetan area in the northwest province of Gansu, according to Tashi Phuntsok, official spokesman for the self-declared Tibetan government-in-exile in India.

He said Jigme Gyatso was released about one year early, likely because of poor health due to harsh treatment in prison.

U.S.-backed broadcaster Radio Free Asia also reported the release.

Jigme Gyatso was sentenced to 15 years in jail in 1996, but that was extended by three years in 2004 after he shouted slogans in prison calling for the return of exiled Tibetan spiritual leader the Dalai Lama.