International standards and human rights principles must be followed, Thailand's prime minister said on Thursday, in response to concerns aired by activists that 48 Uyghurs held for more than a decade had been secretly deported to China.

China confirmed Thailand deported 40 Chinese nationals on Thursday, despite human rights organizations and members of the U.S. government called on Bangkok to not repatriate the Uyghur Muslims.

Thailand's premier said on Thursday international standards and human rights principles must be followed, responding to activists' concerns that 48 Uyghurs held in the country for more than a decade had been secretly deported to China.

Rights groups criticized the Thai government for sending the Uyghurs, a persecuted Muslim minority, back to China where they face the risk of torture and imprisonment.

Dozens of Uyghur men detained in Thailand after fleeing China may have been secretly deported to their home country, activists and rights groups said on Thursday, warning they could face torture and imprisonment on their return.