A crackdown by authorities on small brick factories in two Chinese provinces has freed more than 560 people, including more than 50 under the age of 18, who were allegedly forced to work without pay in often appalling conditions.

Amid a widening scandal that state media say has shocked the nation, authorities in Shanxi and Henan provinces have also detained more than 160 people for involvement in abducting workers or forcing them to labour in virtual servitude.