Turkey has called China's treatment of its minority Uighurs "a great cause of shame for humanity". In a statement on Saturday, Foreign Ministry spokesman Hami Aksoy said it is "no longer a secret" that China has arbitrarily detained more than a million Uighurs in "concentration camps".

Read more: China grilled over Uighur internment camps, civil rights at UN human rights review

He said the Turkic Muslim population faced pressure and "systematic assimilation" in western China.

Aksoy said Turkey has shared with China its position on "all levels" and urged authorities to close the detention facilities and respect human rights.

The minister said Turkey had also learned of the death in prison of famed Uighur musician and poet Abdurehim Heyit, who had been sentenced to eight years over one of his songs.

"This tragedy has further reinforced the reaction of the Turkish public opinion toward serious human rights violations committed in the Xinjiang region," Aksoy said.

"We expect this legitimate response to be taken into account by the Chinese authorities. We respectfully commemorate Abdurehim Heyit and all our kinsmen who lost their lives defending their Turkish and Muslim identity," Aksoy said.

Heyit was a master of the dutar, a type of two-stringed instrument with a long neck that is found in Iran and throughout Central Asia. His detention was considered indicative of China's determination to crack down on Uighur intellectuals and cultural figures in an effort some say to eradicate a separate Uighur language and identity.

Heyit's death could not be independently confirmed.

China had no immediate response to the minister's remarks.

Beijing has intensified a security clampdown on Uighurs in the northwestern region of Xinjiang that was put in place after a bloody 2009 riot. Droves of Uighurs have fled, many travelling to Turkey, where the language and culture are similar to that in Xinjiang.

After months of denying their existence, Chinese authorities under increasing outside pressure acknowledged the system of camps, terming them vocational training centres. They have provided little or no information on how many are interned within them and how long they are being held.

Read more: China holds one million Uighurs in secret camps, says UN panel

Turkish President Recep Tayyip Erdogan had once accused China of "genocide" but has since established closer diplomatic and economic relations with Beijing.