QINGDAO, May 9 -- Five suspects, including a national of the Republic of Korea (ROK), were arrested for smuggling rare earths to the ROK from east China's Shandong Province, Qingdao Customs announced on Saturday.

More than 1,500 tonnes of rare earths and rare metals, worth 110 million yuan (17.7 million U.S. dollars) are involved in the case, officers with the customs said.

In Aug. 2014, one tonne of rare earths and 5 tonnes of ferromolybdenum were intercepted by Weihai Customs, under Qinghai Customs, before the commodity was exported to the ROK.

Investigators found that a Yiwu-based trading company owned by the suspect from ROK surnamed Cho is suspected of purchase and smuggling of rare earths and rare metals.

China meets over 90 percent of world's demand of rare earths, a class of 17 minerals. It's some of the most sought after metals due to their military use and role in green technology like wind turbines and car batteries.