ALMATY--Kazakh police have detained a Chinese-born activist who has campaigned on behalf of ethnic Kazakhs in China, fellow activists said on Sunday.

Serikzhan Bilash, a naturalized Kazakh citizen who was born in the Chinese region of Xinjiang, is a de facto leader and public face of Atajurt, a group that has worked for the release of ethnic Kazakhs from "re-education" camps where activists say more than 1 million ethnic Uighurs and other Muslims are held.

A fiery orator fluent in Kazakh, Chinese and English, Bilash has become a prominent figure on the Kazakh political scene.

Atajurt said security forces had broken into Bilash’s hotel room in Almaty in the early hours of Sunday, detained him and quickly flown him to Astana, the capital of the former Soviet republic.

Bilash’s lawyer, Aiman Umarova, posted a video on Sunday saying she had just arrived in Astana and was going to visit him at the police department where he was being held.

Astana’s police department had no immediate comment.

The government of the Central Asian nation has avoided criticizing China's Xinjiang policies, but negotiated the release of some two dozen people with dual Kazakh and Chinese citizenships detained in China.