Police said they detained 120 suspects including 13 in Zhengzhou, the provincial capital.

More than 35,000 police were dispatched to check 7,500 kilns in Henan during a crackdown on June 9-12.

In the area around Xinxiang, a little to the north of Zhengzhou, police raided 20 brick kilns on Saturday and rescued 23 people including 16 children.

Laborers in the kilns had been enticed there on various pretexts or transported there by human traffickers. Upon arrival they were beaten, starved and forced to work long hours without payment.

In the past two weeks, Chinese media have seized on the plight of children held captive in brick kilns in neighboring Shanxi Province and photos of distraught parents have appeared in the press.

Yang Aizhi, a 46-year-old mother, was one of the people who alerted the public to what was going on.

Her 16-year-old son went missing on March 8 and she has been searching for him ever since. On her travels she heard that the child had managed to escaped from a kiln in Shanxi but she has still not set eyes on him.

Yang went to more than 100 kilns in Shanxi and discovered that "most kilns force children to do hard labor," according to a report in Southern Weekly. Some children even wore school uniforms.

When the children were too tired to push carts, they were whipped by taskmasters, said Yang.

Yang tried to rescue some of the children but was threatened by kiln owners. She was unable to find her son.

Yang and other parents who suspected their children had been kidnapped and forced to work in illegal kilns went to a TV station in Zhengzhou with their story in early May to make the evil practice known and garner public support.

Police have set up a special task force in Henan to investigate the scandal. It will pursue its investigations across the border in Shanxi, according to police sources.

Qin Yuhai, vice governor and police chief of Henan, said "we must do everything we can to fight human trafficking and rescue those held captive".