State Department Spokesman Mark Toner said he wasn't able to release information on the American without a privacy act waiver and that the Swedish working with the North Koreans to resolve the matter.
The Swedish embassy has represented U.S. interests in Pyongyang since the Korean War and has protective powers over American citizens in the region.
According to a U.S. official, the man was detained in North Korea several months ago, and within the last few weeks the Swedes have been able to meet with him.
Spokespersons at the Swedish embassy in Washington and at the U.S. Embassy in Stockholm would not comment other than to say they are "aware of a case with a U.S. citizen."
Toner said he doesn't know exactly why the American is being held or what reason this person had for being there. He added it's unclear if the American is accused of breaking any laws. It would not be out of the ordinary if the North Koreans held this person for crossing the border alone. Nevertheless, Toner said the U.S. would "like him/her released on humanitarian grounds alone."