Three drug-dealing gangs have been busted in southwest China's Guizhou Province, local police said Wednesday.

The gangs purchased drugs from neighboring Yunnan Province, processed them in Guizhou and then sold them in east China's Zhejiang Province and Shanghai Municipality, said the police chief of the city of Bijie, the gangs' home base.

Police have arrested 22 suspects so far, including the gangs' leaders. They have also confiscated 18 kg of heroin.

The suspects will stand trial soon.