Lynnwood's Kenneth Bae moved back into N. Korean labor camp

(CNN) -- Kenneth Bae, the Lynnwood man jailed in North Korea for 15 months, has been moved from a hospital back to a labor camp, the State Department announced Friday.

Department spokeswoman Jen Psaki said in a statement that the United States was "deeply concerned" by the development.

"We also remain gravely concerned about Mr. Bae's health" and again urged Pyongyang to grant him "special amnesty and immediate release on humanitarian grounds," she said.

Bae was arrested in November 2012 in Rason, along North Korea's northeastern coast.

A devout Christian and father of three operated a China-based company specializing in tours of North Korea, according to his family and, a website that friends set up to promote his release.

The North Korean government accused Bae of planning to bring down the government through religious activities.

Last month, he told reporters that he had committed a "serious crime" in the secretive nation and that he had not experienced abusive treatment by the regime.