North Korea has moved imprisoned US citizen Kenneth Bae from a hospital to a labor camp, a US official said Friday, voicing fears for his health.

"The Department of State has learned that the DPRK transferred Mr. Bae from a hospital to a labor camp, a development with which we are deeply concerned," said spokeswoman Jen Psaki.

"We continue to urge DPRK authorities to grant Mr. Bae special amnesty and immediate release on humanitarian grounds."