Police lay in wait in thick grass for more than 30 hours before raiding a secret drug lab in a forested area of Ruyuan county, Guangdong province, late last month.

"We had to climb over wild thorns and cross barriers set up by the suspects during the special police operation," said Ouyang Zhifang, director of the drug enforcement detachment of the Shaoguan city Bureau of Public Security.

"Police seized 313 kilograms of methamphetamine, commonly known as 'ice', 76 kilograms of semifinished meth, plus plenty of equipment for producing the drug," Ouyang told a news conference on Monday.