NANNING, June 20 (Xinhua) -- A total of 18 suspects were arrested and a large amount of narcotics seized during a crackdown on illegal drug-trafficking, according to police in Hechi City, south China's Guangxi Zhuang Autonomous Region.

In October last year, police found some suspected drug traffickers in Guangxi had contacted a suspected drug dealer in Yunnan Province. Further investigation led to a trans-provincial drug trafficking gang which involved several people and a large quantity of drugs.

In April this year, police in Yunnan, Guizhou and Guangxi carried out operations at the same time when the suspects were trading drugs.

A total of 18 suspects were detained, 33.7 kg of heroin and 9.98 kg of methamphetamine were seized. Police also confiscated 2.9 million yuan (about 423,550 U.S. dollars) and seven vehicles, as well as froze more than 3.7 million yuan.

Further investigation is underway.