An ethnic Uighur demonstrator holds a placard with a picture of English soccer club Arsenal's midfielder Mesut Ozil during a protest against China in Istanbul, Turkey December 14, 2019. Ozil has criticized Muslim countries for not speaking up for minorities Uighurs subjected to abuse in China. More than 1 million people have been sent to reeducation camps in the Xinjiang region. REUTERS/Kemal Aslan

"Qurans are being burnt. Mosques are being shut down. Muslim schools are being banned. Religious scholars are being killed. Brothers are forcefully being sent to camps," the Arsenal player posted in Turkish on Twitter and Instagram. "The Muslims are silent. Their voice is not heard," he wrote on a background of a blue field with a white crescent moon, the flag of what Uighur separatists call East Turkestan. Photo: @MesutOzil1088 on Twitter

Ethnic Uighur boys hold placards with the images of English soccer club Arsenal's midfielder Mesut Ozil during a protest against China in Istanbul, Turkey December 14, 2019. The placard reads: "Thank you, Mesut Ozil, on behalf of 35 million oppressed". Ozil has criticized Muslim countries for not speaking up for minorities Uighurs subjected to abuse in China. More than 1 million people have been sent to reeducation camps in the Xinjiang region. REUTERS/Kemal Aslan

An ethnic Uighur boy wears a mask during a protest against China in Istanbul, Turkey December 14, 2019. Ozil has criticized Muslim countries for not speaking up for minorities Uighurs subjected to abuse in China. More than 1 million people have been sent to reeducation camps in the Xinjiang region. REUTERS/Kemal Aslan

An ethnic Uighur demonstrator holds a placard with a picture of English soccer club Arsenal's midfielder Mesut Ozil during a protest against China in Istanbul, Turkey December 14, 2019. Ozil has criticized Muslim countries for not speaking up for minorities Uighurs subjected to abuse in China. More than 1 million people have been sent to reeducation camps in the Xinjiang region. REUTERS/Kemal Aslan

Ethnic Uighur women are seen during a protest against China near the Chinese Consulate in Istanbul, Turkey, December 15, 2019. Former Germany international footballer Mesut Ozil expressed support for Uighurs in Xinjiang, China, on Friday and criticized Muslim countries for their unwillingness to speak out on the poor treatment faced by the Uighur people, a Muslim minority group. REUTERS/Huseyin Aldemir