A comment from Pope Francis in an upcoming book — in which he called ethnic Uighurs in western China a "persecuted” people for the first time — has set the Chinese government on the defense.

The reference to abuses against Uighurs, which Beijing has long denied despite mounting evidence of a brutal crackdown, could tarnish the recent warming of relations between the Vatican and China.

Writing in his new book "Let Us Dream: The Path to a Better Future,” Francis listed "the poor Uighurs” among the people of the world he kept in his mind and prayers.