China committed "serious human rights abuses” against ethnic Muslims in the Xinjiang region and may be guilty of crimes against humanity, the top United Nations rights official said in a report that the government in Beijing had tried to block.

The report from U.N. High Commissioner for Human Rights Michelle Bachelet cited testimony alleging "patterns of torture or other forms of cruel, inhuman or degrading treatment or punishment” as part of a campaign that China said is aimed at clamping down on extremism and terrorism. It said holy places such as the Imam Asim Shrine in southern Xinjiang had been demolished.

Detentions of Uyghurs and other Muslim groups, along with a broader campaign of restrictions and rights violations "may constitute international crimes, in particular crimes against humanity,” Bachelet said.