A report said Pae Jun Ho entered the country Nov. 3 as a tourist and was detained after evidence was found that proved he committed a crime against the country, CNN reported.
The nature of the crime, type of evidence and date of Pae's arrest weren't reported.
The official Korean Central News Agency said Pae "admitted his crime" and faces legal action.
Consular officials from the Swedish Embassy in Pyongyang visited him Friday. Sweden handles U.S. interests in North Korea because the United States and North Korea don't have diplomatic relations.
The BBC said some reports from South Korea indicated Pae is a Korean-American who runs a travel agency and was in North Korea as a guide for a tourist group.