“We are committed to combating China's efforts to pressure governments to forcibly return Uyghurs and other groups to China, where they are subject to torture and enforced disappearances,” Rubio said in a statement.
The Thai embassy in Washington did not immediately respond to a request for comment.
The Uyghurs are a Turkic, majority Muslim group native to Xinjiang in China's far west. After decades of conflict with Beijing over discrimination and suppression of their cultural identity, the Chinese government launched a brutal crackdown on the Uyghurs that some Western governments deem a genocide.
More than 300 Uyghurs fleeing China were detained in 2014 by Thai authorities. By February, 48 Uyghurs remained in Thai detention when authorities prepared to send them back to China despite calls from Thai lawmakers and international officials not to do so.
Rubio condemned the return “in the strongest possible terms,” saying “Uyghurs have faced persecution, forced labor, and torture” in China.
Thai authorities, however, said they were assured by the Chinese government that the men wouldn't face penalties or be harmed.
In Facebook posts, the Chinese Embassy in Bangkok said 40 Chinese nationals who had been “smuggled” were repatriated to Xinjiang on a chartered flight and they had “all returned home and reunited with their families after more than 10 years."
The embassy posted photos of family reunions over naans, nuts and fruits.
Rubio has been a longtime critic of Beijing, and he was twice sanctioned by the Chinese government in 2020 over his support for the rights of Uyghurs and people in Hong Kong.