Turkey has condemned China's mass repression of its Uighur Muslim ethnic minority as a "great shame for humanity" and called on the Chinese government to close its detention camps.
They reportedly hold a million people, including Uighurs, Kazakhs, and other ethnic minority groups.
The criticism comes after a renowned Uighur musician and poet, Abdurehim Heyit, was reported as dead while in custody.
However, a video dated on February 10 was posted by China Radio International's Turkish language service, which appeared to shows Heyit as alive and saying he was "in good health".
“The policy of systematic assimilation against the Uighur Turks carried out by the authorities of China is a great shame for humanity,” Turkish foreign ministry spokesman Hami Aksoy said in a statement on Saturday.
He added the Uighurs are being subjected to "torture and political brainwashing in internment camps and prisons”.
The Chinese embassy in Ankara called on Turkey to withdraw its "false accusations" in a statement, according to the Associated Press news agency.
"Both China and Turkey face the arduous task of fighting terrorism. We are opposed to maintaining double standards on the question of fighting terrorism," it said.
The Uighurs are a Muslim Turkic-speaking minority based in the north-west Xinjiang region of China.
Amnesty International said the detentions appear to be part of an effort by the Chinese government to "wipe out religious beliefs and aspects of cultural identity in order to enforce political loyalty for the State and the Communist Party of China."
Rights activists urged European and Muslim nations to establish a UN investigation into China’s detention and “forced indoctrination” last week.