Members of the Hui minority, who number 10 million, hoped that the state crackdown would not arrive here, in the fertile valleys and loess hills of Gansu province, as it had in Xinjiang, the homeland of the other major Muslim ethnic group in China, the Uighurs.

Hope faded in April. Government cranes began appearing ominously over Hui mosques. A video surfaced on social media showing workers taking apart the Gazhuang mosque’s gold dome, then smashing it into the prayer hall. Local Hui saw an unmistakable metaphor: The Communist Party, which once handled religious life here with a light touch, now ran roughshod over it.

“Women were crying; others, like me, couldn’t believe what was happening,” said Ma Ha, a 40-year-old owner of a noodle shop. “We had 40 years of religious freedom. The winds are changing.”…

That tide of “Sinicization,” as Chinese policymakers call it, is surging nationwide. A recent, unescorted trip through Gansu, a corridor that once ushered Silk Road caravans and Islam into imperial China, revealed an accelerating campaign to assimilate another Muslim minority, the Hui, a Chinese-speaking people with no recent record of separatism or extremism.