North Korea confirmed on Thursday that a man named Jun Young Su has been held there since November.
The reclusive government won't say exactly what he's being held for, but South Korean media is reporting it was for missionary work.
Jun was once a member of Bethel Church in Irvine, but he reportedly hasn't worshipped there in about eight years.
According to the North's official Korean Central News Agency, North Korea informed Washington of the detention, and Jun has been given access to Swedish Embassy officials in Pyongyang. news agency said.
Earlier this week, the U.S. State Department called for North Korea to release one of its citizens and said Swedish officials had visited the American. But it gave no further details. The U.S. - which fought on South Korea's side during the 1950-53 Korean War - doesn't have diplomatic staff inside North Korea and Sweden handles Washington's interests there.
Officially, North Korea guarantees freedom of religion. In practice, authorities 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 story.