Trump raised case in May meeting with Xi, supporters say
Chinese authorities have charged Youlin Chen, a China-born American seismologist who researches underground nuclear tests, with espionage after secretly detaining him in late 2024, according to supporters of the 54-year-old Massachusetts man.
Chen was designated by the State Department as “wrongfully detained” earlier this year, his wife Yufang Rong said in a statement Tuesday. The designation unlocks exceptional U.S. government attention, according to the department. Chen’s case was raised by President Trump during a May meeting with China’s leader Xi Jinping in Beijing, the supporters said. White House spokeswoman Anna Kelly said Trump “wants every American detained abroad to return home” and has reunited over 100 individuals with their families since taking office.
A Chinese Foreign Ministry spokesman, asked about Chen during a Tuesday media briefing in Beijing, said the country is governed by laws and rejected allegations of wrongful detention.
Chen has done research on seismic waves to identify underground nuclear testing by North Korea, according to open-source research he produced. A 2020 paper by Chen cited publicly available data recorded in China to study six underground nuclear explosion tests by North Korea from 2006 to 2017; the paper identifies the State Department as the funder of the work.
“He is a seismologist who works transparently with Chinese colleagues on scientific collaboration,” Rong said in her statement. She rejected the espionage allegations against Chen and said he never held a U.S. government security clearance.
Eric Lebson, chief strategy officer of Global Reach, a nonprofit that focuses on American captives abroad and is working with Chen’s family, described the research as “using earthquake data to interpret North Korean nuclear tests.”
Rong’s statement described Chen as a U.S. government contractor, saying his expertise “would give the Chinese government an opportunity to learn as much as possible about U.S. seismic detection methodologies so they can establish countermeasures that allow them to circumvent the Comprehensive Nuclear Test Ban Treaty.”
The case touches on one of the most sensitive subjects in U.S.-China relations: nuclear capabilities and related technology. The U.S. has accused China of conducting undisclosed nuclear tests underground. During a United Nations conference earlier this year, U.S. Undersecretary for Arms Control and International Security Thomas DiNanno cited one such test in 2020, a disclosure that came months after Trump said the U.S. should restart underground nuclear testing. China says its nuclear system is purely defensive and that it maintains a no-first-strike policy.
Chen’s supporters said he had regularly traveled to China and had been in the country for weeks on a private visit to see family and university collaborators when he was detained at Beijing’s international airport before a flight back to the U.S. in November 2024.
A Beijing native, Chen earned a doctorate in earth sciences from the University of Southern California in 2003 and became a U.S. citizen in 2011. He was traveling with his U.S. passport when detained, his supporters said.
Chen’s supporters said they decided to speak publicly ahead of an expected visit to the U.S. around September by Xi. Rong said Trump has taken “a personal interest in freeing” Chen. No other U.S. citizen is known to be considered wrongfully detained in China, though a number of Americans previously held in China have been freed, including in swaps engineered between the two governments.