North Korea said on Friday it had detained a U.S. university student for committing a "hostile act" and wanting to "destroy the country's unity", the third western citizen known to be held in the isolated state.
The North's official KCNA news agency said Otto Frederick Warmbier entered North Korea as a tourist and "was caught committing a hostile act against the state", which it said was "tolerated and manipulated by the U.S. government".
Gareth Johnson of China-based Young Pioneer Tours said Warmbier, a 21-year-old student at the University of Virginia, was on one of its North Korea tours and detained on Jan. 2.
An official at the U.S. embassy in the South Korean capital Seoul said it was aware of the reported arrest. The U.S. State Department in Washington had no immediate comment.
Johnson said Young Pioneer Tours was in contact with Warmbier's family and U.S. officials.
"We are in touch with Otto's family, the U.S. State Department and the Embassy of Sweden in Pyongyang and doing all we can to secure his release," Johnson told Reuters.
The Swedish Embassy represents U.S. interests in North Korea.
KCNA said Warmbier had entered the country with an "aim to destroy the country's unity". It did not elaborate.
According to his social media profiles, Warmbier is from Cincinnati and is an Echols Scholar, awarded to the top seven percent of incoming first year students at the University of Virginia, where he majors in economics with a minor in global sustainability.
In previous years, Warmbier visited countries including Cuba, Ireland and Israel, according to his Facebook profile.
Warmbier was detained four days before North Korea conducted its fourth nuclear test in violation of UN sanctions, drawing condemnation from its neighbors and the United States.
South Korea warned that the United States and its allies were working on further sanctions to inflict "bone-numbing pain" on North Korea after its latest nuclear test, and urged China to do its part to rein in its neighbor.
North Korea has a long history of detaining foreigners, and the U.S. and Canadian governments advise against travel there.
Pyongyang has in the past used detained U.S. citizens to extract high-profile visits from the United States, with which it has no formal diplomatic relations.
A South Korean-born Canadian pastor was arrested in North Korea last year and given a life sentence for subversion. Earlier this month, a Korean-American man told CNN in Pyongyang that he was being held by the state for spying.
In 2014, Pyongyang released three detained Americans. Last October, it freed a South Korean national with a U.S. green card after holding him for six months.