China has opened a national investigation into a slave labor scandal in central China, where as many as 1,000 people are believed to have been forced into a brutal human trafficking ring.
China's official Xinhua news agency says a team of investigators will be sent to brick kilns and coal mines in Shanxi and Henan provinces, where more than 500 people, many of them children, have been freed in recent days. Officials say they believe hundreds more could be trapped at the work sites.
Media reports say the owners of the kilns ran their operations like prisons, with thugs who beat children and used fierce dogs to maintain control. Reports also describe the workers as having been beaten and starved.
Police say 24 suspects have been detained so far in a raid.
Tens of thousands of officers were involved in the three-day raid at 7,500 brick kilns in the two provinces.
Some reports say children were abducted from train stations and sold to brickmakers. One kiln owner says he paid $50 for a boy.
Reports say police believe the slave trade has been going on since at least March, and possibly for years.
Some information for this report was provided by AFP, AP and Reuters.