U.S. officials say an American citizen detained in North Korea for 15 months has been returned to a labor camp.
A State Department spokeswoman said Friday that 45-year-old Kenneth Bae was transferred from a hospital to a labor camp on January 20 and that Washington is "gravely concerned about his health."
Spokeswoman Jen Psaki said Swedish embassy officials had visited Bae in the camp on Friday.
Psaki urged Pyongyang to grant Bae special amnesty and his immediate release on humanitarian grounds.
North Korea sentenced Bae to 15 years of hard labor on charges of trying to overthrow the government. Earlier calls for his release on humanitarian grounds have gone unanswered.
The news of Bae's transfer coincided with a story in a pro-Pyongyang newspaper based in Japan, Choson Sinbo, reporting that a U.S. envoy was expected to visit Bae.
Choson Sinbo said a reporter had interviewed Bae at the prison, and Bae said he had been notified that an American envoy on North Korean human-rights issues, Robert King, could visit as soon as Monday and no later than the end of the month.
The State Department says it has a longstanding offer to send Ambassador King to North Korea in support of Bae's release.
Bae was born in South Korea and immigrated to the United States with his parents and sister in 1985. He had been living in China as a Christian missionary for about seven years before his arrest.
Within the last few years, he began leading small tour groups, mostly of American and Canadian citizens, into a "special economic zone" designed to encourage commerce in northeastern North Korea.