A Chinese-American man in his 50s who conducted research on detecting North Korean nuclear tests has been detained in China for 20 months, Reuters reported.

This issue could become a point of contention in U.S.-China relations, which have focused on strategic stability. It is reported that U.S. President Donald Trump requested his release from Chinese President Xi Jinping during his visit to China last May.

Reuters reported on the 13th (local time) that Lin Chen (54), a Chinese-born American seismologist, has been held in detention in China for over 20 months.

Chen was reportedly arrested at Beijing Capital International Airport on November 5, 2024, while attempting to return to his home in Boston, Massachusetts, after visiting family in China.

On March 19, U.S. Secretary of State Marco Rubio designated Chen as "wrongfully detained." Chen is reportedly the only one among the dozen or so Americans detained in China to be officially designated as such.

Although Chen was indicted on espionage charges in May of last year, he has not yet stood trial. His family in the United States fears that he could face a sentence ranging from life imprisonment to the death penalty.

There is speculation in the U.S. that China’s detention of Chen may be an attempt to leverage his expertise regarding North Korean nuclear tests to cover up its own underground nuclear testing.

As a seismologist, Chen had been researching the detection of North Korean nuclear tests. In December 2020, he published a paper analyzing methods to distinguish between seismic waves caused by natural earthquakes and those generated by North Korean nuclear tests.

Reuters reported that the paper was written with support from the U.S. Department of State’s Bureau of Arms Control, and its cover stated that it was cleared for public release.

Last February, the Trump administration accused China of using a method to reduce the intensity of shockwaves through underground nuclear testing in June 2020. China has denied conducting any nuclear tests.

Both the United States and China have signed, but not ratified, the Comprehensive Nuclear-Test-Ban Treaty (CTBT).

Trump and Xi (left) meeting in Beijing last May [AP=Yonhap News File Photo]

The issue of Chen’s release could serve as a source of conflict in U.S.-China relations, which are currently emphasizing "strategic stability." Given that Chen is a scholar who researched North Korean nuclear test detection, his detention also has the potential to indirectly provoke North Korea.

It is reported that President Trump requested Chen’s release to President Xi during his visit to China in May, and that Xi responded that he would look into the matter.

President Xi is scheduled to make a reciprocal visit to the U.S. in September; if no significant progress is made by then, it is highly likely that President Trump will raise Chen’s release as a key agenda item again.

Chen's family stated that the Trump administration had kept Chen’s detention secret in the hopes of securing his release through high-level negotiations.

According to reports, during the early stages of his detention, Chen was forced to sit in a hard chair all day without being able to stand or exercise. His family claims he was unable to obtain necessary medications, including those for diabetes, which led to a weight loss of up to 18kg.

His family added that Chen has been interrogated over 100 times so far, and that even when U.S. consular officials visit, Chinese authorities are present, preventing any free or private conversation.