Beijing has condemned Turkey over its claim that a celebrated musician from China's Turkic Muslim Uighur ethnic group has died in custody.
Foreign ministry spokeswoman Hua Chunying said a brief video clip of Abdurehim Heyit issued by state media proved he was alive and in good health and showed Turkey's statement was an "absurd lie".
"The Turkish side has made a very bad mistake which is quite irresponsible. We express firm opposition to this," Ms Hua told reporters at a daily briefing. China has filed a formal complaint and called on Turkey to reveal the source of its information, she said.
Heyit had reportedly been sentenced to eight years over one of his songs. Ms Hua said he had been taken into custody for endangering national security and his case was under investigation.
The row over Turkey's criticism contrasts with the close economic relationship between the two countries. Turkey depends on Chinese financing for major infrastructure projects, while China sees Turkey as an important link in its gargantuan Belt and Road project to expand its economic reach abroad.
Turkey's claim of Heyit's death came in a foreign ministry statement on Saturday calling China's treatment of Uighurs "a great cause of shame for humanity" - a rare show of public criticism by a majority Muslim nation.
China has interned an estimated 1 million Uighurs and other Muslim minorities in re-education camps, where they are forced to renounce Islam and swear fealty to ruling Communist Party leader Xi Jinping.
Turkish foreign ministry spokesman Hami Aksoy said it was "no longer a secret" that China has arbitrarily detained more than a million Uighurs in "concentration camps". He said the Turkic Muslim population faced pressure and "systematic assimilation" in western China.
In the video released by state media outlet China Radio International, Heyit said he was being investigated for criminal activity, but was in good health and had "never been abused".
At the start of the video, Heyit states his name and gives the date as February 10, 2019. The authenticity of the video could not be verified and it was not clear where and by whom it had been filmed.
However, Ms Hua said that after checking with the "relevant department in Xinjiang", the ministry had confirmed the video's legitimacy.
Chinese state media have a long history of broadcasting confessions by both Chinese and foreign citizens who afterwards say they were compelled to participate against their will and forced to read a script.
Although Turkey's criticism appeared without warning, Chinese diplomats responded with alacrity. The Chinese Embassy in Turkey swiftly issued a lengthy defence of Chinese policies, calling Mr Aksoy's comments "completely unacceptable" and accusing Turkey of "maintaining double standards on the question of fighting terrorism".
Amid the clampdown, multitudes of Uighurs have fled, many travelling to Turkey, where the language and culture are similar to those in Xinjiang.