QINGDAO, Nov. 4 -- Customs authorities in eastern China's port city of Qingdao announced on Friday that they had busted a gasoline trafficking ring.

Qingdao customs received a tip-off about smuggling practices in August. They joined hands with provincial marine police to launch raids on August 26, on sea and in Weihai City. More than 270 police officers and six vessels were used in the operation.

Twenty-seven suspects and four vessels, carrying 700 tonnes of gasoline were seized, customs authorities said.

The suspects drove their own vessels and rented others to purchase gasoline from smugglers on the open sea, according to customs authorities.

Since the end of 2015, about 40,000 tonnes of gasoline have been smuggled through several coastal cities in Shandong Province, worth a total over 200 million yuan (about 30 million U.S. dollars), customs authorities said.