Pyongyang University of Science and Technology (PUST) has named the American citizen detained in North Korea on April 22 as Kim Sang-duk, also known as Tony Kim.

The Korean-American lecturer taught at the North Korean university for several weeks prior to his arrest.

Tony Kim was arrested just as he was about to leave Pyongyang.

North Korean authorities have not yet disclosed the reason for the arrest.

According to South Korean news agency Yonhap, Tony Kim, who is in his late 50s, was involved in aid programs and had been in North Korea to discuss relief activities.

Kim Sang-duk reportedly taught at Yanbian University of Science and Technology in China, which is affiliated to PUST.

Image source CNN

PUST’s chancellor, Park Chan-mo, was quoted by Reuters as saying that Tony Kim “had been involved with some other activities outside PUST such as helping an orphanage”.

The US State Department said it was aware of reports of the detention, but would not comment further because of “privacy considerations”, US media reported.

The detention comes as tensions ratchet up in the Korean peninsula, with US warships steaming towards the region as Pyonyang threatens a “super-mighty pre-emptive strike”.

Chinese state media reported that President Xi Jinping and President Donald Trump spoke on the phone again on April 24.

Xi Jinping reiterated his call for calm saying he “hopes relevant parties exercise restraint, and avoid actions that would increase tensions”, and both leaders promised to keep in touch regarding the Korean peninsula, reports said.

US officials have not yet confirmed the call.

The US has in the past accused North Korea of detaining its citizens to use them as pawns. Tony Kim is one of three US citizens currently being held by North Korea.

In April 2016, Kim Dong-chul, a 62-year-old naturalized US citizen born in South Korea, was sentenced to 10 years’ hard labor for spying. He was arrested in October 2015.

American student Otto Warmbier, 21, was arrested in January 2016 for trying to steal a propaganda sign from a hotel while visiting North Korea.

Otto Warmbier was given 15 years hard labor for crimes against the state in March 2016.