Tens of millions of Chinese now identify as Christians, and the number has grown rapidly, posing challenges for a government that is officially atheist and wary of threats to its power.

As China’s senior Communist Party members anoint its future leaders, President Xi Jinping is poised to solidify his position and power at next week’s party congress.

The Muslim separatist group, based in the Xinjiang province in northwest China, presents a heightening security challenge for Beijing.