The US and its intelligence allies have described "overwhelming" evidence of China's human rights abuses of Uighurs and other minorities in China's Xinjiang Uygur Autonomous Region.
Their comments came as the US, Britain, Canada and the European Union imposed coordinated sanctions on Monday on Chinese officials accused of being involved in such abuses.
Foreign ministers of the so-called Five Eyes intelligence-sharing alliance expressed deep concern over the issue. The group consists of the US, Britain, Canada, Australia and New Zealand.
Their joint statement said, "The evidence, including from the Chinese Government's own documents, satellite imagery, and eyewitness testimony is overwhelming."
It added that China's extensive program of repression included severe restrictions on religious freedoms, the use of forced labor, mass detention in internment camps and forced sterilizations.
The statement urged China to release Uighurs and others who were being arbitrarily detained, and also grant access to UN investigators.
China denies all allegations of abuse.