Across China’s west, the Communist Party is placing children in boarding schools in a drive to assimilate a generation of Tibetans into the national mainstream and mold them into citizens loyal to the party.

Tibetan rights activists, as well as experts working for the United Nations, have said that the party is systematically separating Tibetan children from their families to erase Tibetan identity and to deepen China’s control of a people who historically have resisted Beijing’s rule. The activists have estimated that around three-quarters of Tibetan students age 6 and older — and others even younger — are in residential schools that teach largely in Mandarin, replacing the Tibetan language, culture and Buddhist beliefs that the children once absorbed at home and in village schools.

When China’s top leader, Xi Jinping, visited one such school in the summer, he inspected a dormitory that appeared freshly painted and as neat as an army barracks. He walked into a classroom where Tibetan students, listening to a lecture on Communist Party thought, stood and applauded to welcome him.