China Radio International's Turkish language service released a 26-second video online late Sunday, showing a man said to be Abdurehim Heyit stating that he was in "good health".
Turkey said the Uyghurs faced pressure and "systematic assimilation" in western China.
Turkish Foreign Ministry spokesman Hami Aksoy said in a statement, "It is no longer a secret that more than one million Uighur Turks incurring arbitrary arrests are subjected to torture and political brainwashing in internment camps and prisons".
In Saturday's statement, Turkey called on the global community and the United Nations secretary-general "to take effective measures in order to bring to an end this human tragedy in Xinjiang". "I'm in the process of being investigated for allegedly violating the national laws".
Mr Aksoy was referring to China's mass incarceration of the Muslim Uyghur minority situated in the north-western province of Xinjiang - a region incorporated into modern China after leaders of the East Turkestan Republic surrendered to the Chinese Communist Party in 1949.
"Allegations that the Chinese government is liquidating the ethnic, religious and cultural identities of Uighurs and other Muslim communities are totally baseless, " the statement concludes.
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In January, President Hassan Rouhani said his country was experiencing its worst economic crisis since the overthrow of the Shah. Mahmoud Hemmati, 35, was pushing his 68-year-old mother, Parivash Fakheri, in a wheelchair.
But in a video that appeared today, a man - purported to be Mr Heyit - is seen rocking slightly from side to side, wearing a white and black sweater and delivering a short statement against a drab grey background.
Abdurehim Heyit is thought to have been serving an eight-year sentence in the Xinjiang region, where up to a million Uighurs are reportedly being detained.
China hit back on Monday against Turkish criticism over its treatment of ethnic Uighurs and denied Ankara's claim that a renowned poet from the Muslim minority had died in custody, calling it an "absurd lie".
Outside of the camps, more than 10 million Turkic Muslim minorities in the region are subjected to a dense network of surveillance systems, checkpoints and interpersonal monitoring, which severely limit their personal freedom.
Worldwide rights groups say China routinely coerces detainees into making videotaped confessions which are then broadcast through state media to serve the government's propaganda objectives.
"I'm now in good health", he says, and after a pause, adds: "and have never been abused".
China denied the existence of the so-called "de-radicalisation" facilities for months before saying they were, in fact, vocational training centres created to combat extremism. We expect this legitimate response to be taken into account'.