The wife of a U.S. citizen who was detained in North Korea over the weekend is appealing for his immediate release.
"I hope everybody joins in resolving this issue as soon as possible," said Kim Mi Ok, the wife of agriculture researcher Kim Hak-song, who was arrested Saturday on suspicion of "hostile acts" against the North Korean government.
North Korea's state-run news agency KCNA reported Sunday that "a relevant institution is now conducting detailed investigation" into Kim's crimes, but provided no further details on his detention.
The arrest of Kim, who had been working at the Pyongyang University of Science and Technology (PUST), brings to four the number of U.S. citizens being detained in North Korea amid rising tensions over that country's nuclear weapons development program.
PUST, which employs a substantial number of foreign staff, issued a statement saying, "We understand that this detention is related to an investigation into matters that are not connected in any way with the work of PUST."
Speaking to the VOA Korean Service on Sunday, Kim Mi Ok said her husband was arrested as he tried to return to the couple's home in Dandong, China. She said PUST told her over the phone that Kim had boarded a train in Pyongyang. However, he never arrived.
"I went to greet him at the Dandong station, and I waited until the last person to get off the train, but he was nowhere to be seen," said Kim's wife, who is one of some 2 million ethnic Koreans born in China.
Kim Mi Ok said her husband has been involved in agricultural development work at the university's experimental farm since 2014. He was working toward establishing an organic fermentation fertilizer plant, she added. PUST is the only privately funded university in North Korea.
An agricultural expert, Kim wanted to help North Korea alleviate food insecurity by supplying new agricultural technology, his wife told VOA. "So I have no idea why they detained him."
An ethnic Korean born in China in 1963, Kim studied agriculture at a Chinese university, then studied theology in Los Angeles between 1995 and 2005. Kim became a naturalized U.S. citizen in 2008.
The U.S. State Department said "the security of U.S. citizens is one of the department's highest priorities," and it will work with the Swedish embassy in Pyongyang, which represents American interests in North Korea, to try to secure the freedom of the four detained Americans.
On Monday, White House spokesman Sean Spicer said Washington will work through the Swedish Embassy in North Korea to free the Americans.
"Obviously, this is concerning, Spicer said.
Tony Kim — or Kim Sang Dok — also a PUST staffer, was arrested on April 22 at an airport in Pyongyang on charges of "hostile acts" toward the regime.
Korean American Kim Dong Chul is serving 10 years on espionage charges and Otto Warmbier, a University of Virginia student, was sentenced to 15 years of hard labor in 2016 for removing a propaganda poster.
Analysts say North Korea often attempts to use foreign detainees to wrest outside concessions, which in the past have sometimes involved high-profile American missions sent to secure the release of detainees.
Jenny Lee contributed to this report which originated with the VOA Korean Service.