I saw this

State Department, Swedish Embassy to work on caseThe detention was confirmed by Martina Aberg, deputy chief of mission at the Swedish Embassy in Pyongyang.The embassy represents US interests in North Korea, since Washington and Pyongyang do not have direct diplomatic relations.”He was prevented from getting on the flight out of Pyongyang,” Aberg said. “We don’t comment further than this.”The US State Department on Sunday said it was working on the case.”We are aware of reports that a US citizen was detained in North Korea,” said a department official. “The protection of US citizens is one of the Department’s highest priorities.”The official said the United States would work with the Swedish Embassy on the matter, but did not provide further comment.

Source: American detained in North Korea – CNN.com