China has hit back against claims by Turkey that a famous Uighur poet and musician has died while imprisoned in Xinjiang, where Beijing’s severe policies toward the Muslim minority group have prompted international outcry.

Turkey’s foreign ministry said on Saturday it had learned that poet and musician Abdurehim Heyit had died while serving an eight-year prison sentence. In a rare rebuke of China, the ministry said Beijing’s treatment of Uighurs was “a great embarrassment for humanity”.

The Uighurs are a Turkic Muslim group in China’s far north-western territory of Xinjiang, where a counter-terrorism campaign has led to as many as a million minority Muslims being detained in a network of internment camps. Turkey, now one of the few Muslim-majority countries to criticise China, has for years welcomed Uighur refugees.

On Sunday, the state-owned China Radio International’s Turkish edition released a video of Heyit, dated 10 February while the Chinese embassy in Turkey said Ankara had “seriously violated the facts”.

In the 25-second video a pale-faced Heyit, seated in front of a grey wall, says he is being investigated for “allegedly violating national laws”. “I’m now in good health and have never been abused,” he said, according to the subtitled video.

Heyit, known throughout the Turkic-speaking world for his poetry and performances of traditional Uighur music, was believed to have been arrested in April 2017, according to former colleagues. Heyit’s son was reportedly able to visit him, but friends say they have heard not heard from him since he was detained.

The video also marks a rare rebuttal from China. It is uncommon for Beijing to respond directly to specific cases of individuals believed detained in Xinjiang.

“This situation doesn’t undermine efforts so much as it shows that outcry can force China to respond,” Elise Anderson, a PhD candidate at Indiana University, focusing on Uighur music, wrote on Twitter. “We should see it as remarkable that they have circulated this video when … they have been deafeningly silent about the whereabouts of so many of the disappeared.”

In a country where televised forced confessions are not uncommon, the video raises more question than it answers. Heyit’s statement that he is under investigation contradicts other reports that he has been sentenced to prison. It also indicates Heyit has been detained for more than a year without being formally charged.

He was one of the first of a string of Uighur musicians and public cultural figures to have been detained in Xinjiang. The folk singer, while employed by a government entertainment troupe, was known for veering into the political with songs like Stubborn Guest, a thinly veiled reference to Chinese control of the far western region of Xinjiang.

In another song called Query of the Conscience, he sings: “When my conscience asks what I live for, I will answer: For my people, my homeland.”