SAN FRANCISCO (AFP) ― Kenneth Bae, a U.S. citizen jailed in North Korea, has been moved from a prison camp to a hospital in Pyongyang as his health deteriorates, U.S. media reported.

Bae’s sister Terri Chung told The New York Times and CNN on Sunday that her 45-year-old brother has lost more than 23 kilograms and has problems with his kidneys and liver.

“He has a host of ailments,” Chung said. “Some of them have worsened considerably enough to warrant a hospital transfer.”

Chung said that the U.S. State Department informed the Bae family that the Swedish ambassador met with Kenneth in the hospital on Friday.

The United States has no diplomatic ties with North Korea, and the Swedish embassy in Pyongyang acts on behalf of Washington in consular matters.

Bae, a Korean-American tour operator, was arrested in November as he entered the northeastern North Korean port city of Rason.

He was sentenced to 15 years of hard labor for subversion and began serving his time on May 14, according to Chosun Sinbo, a pro-Pyongyang newspaper published in Japan.

North Korean state media said earlier that Bae had been convicted of seeking to “topple” the regime in Pyongyang.

The North’s court has described Bae as a militant Christian evangelist who smuggled inflammatory material into the country and sought to establish a subversive base in Rason.

In July, Bae’s family received letters from Kenneth for the first time since he was jailed. In the letters Bae wrote about the poor prison conditions, and asked that the U.S. government work to get him released, The Times reported.

Chung told the newspaper that last week her family received another pack of letters with similar wording.

Bae was sentenced at a time of heightened military tensions on the Korean peninsula, suggesting that Pyongyang hopes to use him as a bargaining chip in talks with Washington.

The United States wants Bae released on humanitarian grounds.