A prominent activist campaigning for the release of ethnic Kazakhs caught in a sweeping crackdown on Muslims in China has been arrested in the Kazakh city of Almaty.

Leila Adilzhan told The Associated Press by phone that her husband, Serikzhan Bilash, head of the advocacy group Atajurt, called her Sunday morning from a policeman's phone saying he had been arrested and had been taken to Astana, the capital of Kazakhstan.

The detention of possibly more than a million Uighurs (WEE-gurs), Kazakhs and other ethnic minorities into Chinese internment camps has been a touchy issue in neighboring Kazakhstan.

Atajurt became prominent last year for supporting the relatives of those detained. They wrote letters to embassies and the United Nations, and taped hundreds of testimonies by relatives looking for their loved ones.