Chinese police say they have rescued 178 children and arrested 608 suspects in a crackdown on suspected human trafficking gangs.

China's public security ministry said Wednesday that over 5,000 police officers made the arrests last month during a joint operation in 10 different provinces across China.

Police first uncovered a child trafficking group in the southwestern province of Sichuan while investigating a traffic accident in May. Authorities later found a similar group in the southeastern province of Fujian.

China has a thriving black market in children and women. Observers say China's one-child policy and lax adoption rules help set the stage for a rampant child market, mostly involving buyers who want more children or who want them as slave labor.

The state-run news agency Xinhua says national police have broken up over 7,000 human trafficking groups since 2009, involving more than 18,000 children and 34,000 women.