Tony Kim, 58, also known as Kim Sang Duk, is being held by the rogue state after being accused of committing “hostile acts with an aim to subvert the country”.
The official Korean Central News Agency (KCNA) said on Wednesday that US citizen Kim Sang-duk, also known as Tony Kim, had been arrested at Pyongyang’s airport on April 22.
He was detained for “committing criminal acts of hostility aimed to overturn the DPRK,” the KCNA added, using an acronym for the Democratic People’s Republic of Korea, the official name of North Korea.
The man was teaching accounting at the Pyongyang University of Science and Technology, AP reported citing the university’s chancellor.
Law enforcement authorities were conducting an investigation into the crime, the agency said.
The recent detention brought the number of Americans held in the country to three.
Otto Warmbier, who was 21 at the time of his arrest in January 2016, was sentenced to 15 years of hard labor in prison after he confessed to trying to steal a propaganda banner.
Kim Dong Chul, who was born in South Korea but is also believed to have US citizenship, is also serving a sentence of 10 years for espionage.
The recent arrest came as tensions have been on the rise on the Korean Peninsula in recent weeks.
Unsettled by North Korean missile and military nuclear programs, the United States has adopted a war-like posture, sending a strike group and conducting joint military drills with North Korea’s regional adversaries Japan and South Korea.
Pyongyang defends its missile and nuclear programs as a means of protecting the country from US hostility.
In addition to the strike group, which includes the large USS Carl Vinson aircraft carrier, Washington deployed two supersonic bombers over the Korean peninsula during a joint exercise with South Korea’s air force on Monday.
Pyongyang protested the flyover, warning that the US “reckless provocation is pushing the situation on the Korean Peninsula closer to the brink of nuclear war.”
North Korea says the annual drills are rehearsals for invasion. Pyongyang is also concerned by the permanent presence of American forces in the region.
The US has also angered the North by deploying the THAAD missile system to the South Korean soil. Washington said Monday that the system is now operational.