North Korea said on Thursday it was its sovereign right to “ruthlessly punish” American citizens it has detained for crimes against its government system.
Pyongyang also said that US media’s description of such arrests as a bargaining ploy was “pure ignorance.”
The North’s KCNA news agency said the crimes of recent Americans detained by its authorities will soon be revealed.
Two American citizens affiliated with a private university in the North’s capital have been detained in the past month.
On May 7, Kim Hak-song became the fourth American citizen currently detained by the repressive regime, on charges such as espionage and crimes against the state.
The American who has been held the longest in North Korea at this time is Kim Dong-chul, a naturalised American citizen who was born in South Korea.
Kim is a businessman in his mid-60s who at one time lived in Fairfax, Virginia.
Tony Kim, who also goes by his Korean name, Kim Sang-duk, a 58-year-old American citizen who was temporarily teaching an accounting course at the Pyongyang University of Science and Technology.
He was detained at the airport while trying to fly to China with his wife on April 22.
It is unclear what prompted his detention, but he has been charged with hostile criminal acts with an aim to subvert the country.
Also in detention is Kim Hak-song.
Reports however said that little is known about Kim Hak-song.
The regime’s official news agency said on May 6 that he was being held for “hostile acts against the country,” although details about the alleged acts were not provided by North Korean authorities.
Kim had also been working at the Pyongyang University of Science and Technology, in agricultural development with its “experimental farm,” the university said in a statement.
He was arrested on May 5 as he was “about to leave, after a visit of several weeks,” it added.