Guan Heng, 38, underwent an immigration hearing in New York on Monday after being detained by US Immigration and Customs Enforcement (ICE) in August, his mother said in an interview.

The case could see him taken out of the United States and potentially landing back in China eventually.

"I'm really, really worried that things will be very bad for him if he is made to return," Guan's mother, Luo Yun, told AFP in Chinese.

"If he has a chance to remain in the United States, he'll at least be safe," she said. "With everything that has happened to him, I'm incredibly anxious and upset."

In late 2021, Guan had published a 20-minute long video online, detailing his travel around the northwestern Xinjiang region in China.

He was visiting places identified by a BuzzFeed investigation as detention facilities for Uyghurs and other Muslim minorities -- or likely sites for such centers.

Beijing has been accused of detaining more than a million Uyghurs and other Muslims in its northwestern region, in a campaign that the United Nations previously said might constitute "crimes against humanity."

China vehemently denies these allegations, saying its policies have rooted out extremism in Xinjiang and brought about economic development.

Guan left China after filming the videos, eventually entering the United States following travels through South America.

Around that time, he told his mother that he did not plan to return to China.

"As for the contents of the clips that he later posted -- I didn't know about them," his mother said.

The pair stayed in touch, and she recalls receiving a text in August from a friend of Guan's, informing her that he had been detained during an operation by the US Immigration and Customs Enforcement (ICE) agency.

When she managed to contact him, she said, "his emotional state was one of extreme panic and breakdown."

Luo added that her family members in mainland China have also been questioned by authorities about their ties to Guan, shortly after he published his video.

"I'm heartbroken," she said. "I'm not only crying for my child, but the situation that our family is facing."

Guan's supporters say he is being held in a Broome County facility in upstate New York, and his name appears on an online page of ICE detainees.

"My only consideration now is for him to catch a breather and come out alive," said Guan's mother.