South Korea has arrested an oil broker for allegedly supplying around $14.7 million (18 billion Korean won) worth of diesel fuel to North Korea without government approval, the coast guard announced Monday.

Korea Coast Guard’s West Sea regional division said in a press release that the unnamed broker carried out over 35 ship-to-ship transfers to smuggle around 18,000 tons of diesel between Oct. 2021 and Jan. 2022.

The coast guard’s investigation team found that the broker transported the diesel fuel from the ROK using a Russian oil tanker owned by a domestic oil company and then transferred the fuel to