Wife of US seismologist detained in China says Trump will ask Xi to free him

Youlin Chen, 54, is one of two Americans held by Beijing whom the US has designated as "wrongfully detained," making their release a top priority.

The wife of a US expert on North Korean nuclear tests who has been imprisoned in China since late 2024 said on Tuesday the White House has assured her that US President Donald Trump will ask Chinese leader Xi Jinping to free her husband when the pair meet this week.

Yufang Rong said she feared that Beijing planned to try her Chinese-born husband, Youlin Chen, on fabricated espionage charges even though his US-funded research was openly published, used publicly available data and was done in collaboration with Chinese scientists.

Trump will welcome Xi on Wednesday for their second meeting since May as the heads of the world's leading powers seek stability amid tensions ranging from trade to Iran and Taiwan.

Rong said she was assured during a Tuesday meeting at the White House with officials from the State Department and National Security Council that Trump would ask Xi to free her husband.

Chen, 54, is one of two Americans held by Beijing that the US has designated as "wrongfully detained," making their release a top priority. The other is Min Zin, a scholar arrested in June.

Rong said she was told that Trump also would press Xi to release Min Zin.

Trump raised Chen's case with Xi during a visit to Beijing in May, but it produced no action, Rong said.

"Resolving the wrongful detentions of US citizens is always a top priority for the president," a senior US official said, speaking on the condition of anonymity to discuss sensitive matters.

A Chinese foreign ministry spokesperson said that the "relevant US person" is suspected of engaging in activities that endanger China's national security and violate Chinese law.

"China is a country with rule of law, and there is no such thing as wrongful detention," spokesperson Guo Jiakun told reporters in Beijing, without elaborating and referring to Chen.

Chen's research funded by US Air Force, State Department

Chen, whose detention was revealed by Reuters in July, is a seismologist with a US government contractor. His work detecting shockwaves from North Korean underground nuclear tests has been openly funded by the State Department and the US Air Force Research Laboratory.

He became a US citizen in 2011 and settled in the Boston area.

He was arrested by Chinese state security officers on November 5, 2024, at Beijing International Airport as he prepared to fly home after visiting family and lecturing at two universities. Rong said her husband had been interrogated more than 100 times.

"I can't imagine how hard his life is there every day," she said.

She believes that China wants to use her husband's expertise to improve its ability to conceal nuclear tests using decoupling, a technique in which a device is detonated inside a large underground chamber to reduce the size of the shockwaves.

The US has accused China of using decoupling to try to mask a low-yield nuclear test blast on June 22, 2020. China, which, like the US, has signed but not ratified a 1996 international ban on nuclear tests, denies conducting the test.

US officials obly allowed to visit Chen once a month

US embassy officials had been allowed to visit Chen for about 30 minutes once a month, always in the presence of Chinese officials, Rong said. They read out letters she had written to him, and he dictated his replies.

"They record his appearance, his mental status, and just anything that they observe," she recounted, adding that Chen's Chinese lawyer was not allowed to discuss his visits with her.

Rong is concerned about the conditions of her husband's confinement, where she said he received substandard medical care and food. He suffered from high blood pressure and diabetes.

Asked what she would say to her husband if she could see him, Rong replied: "'Be strong. Be optimistic. There are a lot of people helping you. You will come back for sure.'"