North Korea arrested an American tourist last month for inappropriate activities, its state media has said.
A report on the KCNA news agency said the man had entered North Korea on 29 April, but was detained as he was leaving the country.
The report said he has been questioned, but gave no more details. Japanese agency Kyodo said the tourist was held because he left a Bible at a hotel.
If confirmed, North Korea would now be holding three US citizens.
US-Korean missionary Kenneth Bae was arrested in November 2012 and is serving 15 years of hard labour after being convicted of trying to overthrow the government.
In late April, KCNA said an American named Matthew Todd Miller had been taken into custody on 10 April.
North Korea uses the arrested Americans as diplomatic bargaining chips.
In the past, senior US figures including former president Bill Clinton have travelled to the country to ensure the release of American detainees.