FUZHOU, Dec. 19 (Xinhua) -- Chinese police have busted a drug production workshop at an abandoned factory in Zhoukou City in central China, seizing 20 suspects, authorities said Tuesday.

Police officers from Putian City in Fujian Province and Zhoukou City in Henan Province raided the factory in Zhoukou in early October.

They seized more than 1.5 tonnes of ephedrine, a raw material for methamphetamine, 70 tonnes of other raw materials and some drug-manufacturing equipment, Putian public security bureau said.

Putian police obtained information in September that a number of Fujian residents were producing drugs in Zhoukou. After preliminary investigation, they tracked down the gang.

Further investigation is underway.

Chinese police arrested 168,000 suspects for drug production or trafficking and solved 140,000 drug cases last year.