NANJING - The Chinese coast guard detained 48 people for smuggling diesel fuel and seized seven ships as well as 3,650 tonnes of fuel, authorities in East China's Jiangsu province said Tuesday.

The seized fuel is estimated to be worth around 20 million yuan ($3.12 million), according to authorities.

The ships sailed from coastal Zhejiang and Fujian provinces to the open sea to pick up the fuel, then smuggled it to Jiangsu, authorities said.

Local coast guard received reports of illegal fuel trade in the Nantong sector of the Yangtze River on June 7 and sent patrol ships to investigate. The guard caught the suspected smugglers on June 8.

The case is under further investigation.