This comes after a U.S. envoy to North Korea "expressed regret at the incident on behalf of the U.S. government."
Eddie Jun is accused of committing a serious crime against North Korea.
Pyongyang has not revealed what that crime was, but South Korean media has reported Jun was accused of spreading Christianity.
North Korea gave Jun medical treatment and allowed him to make regular contact with the Swedish Embassy in Pyongyang, which represents U.S. interests in the country, and to talk by phone with his family, North Korea's news agency said.
North Korea officially guarantees freedom of religion, but authorities often crack down on Christians, who are seen as a Western-influenced threat to the government. The distribution of Bibles and secret prayer services can mean banishment to a labor camp or execution, defectors from the country have said.
The Associated Press contributed to this report.