A Hong Kong-flagged vessel was caught transferring oil to North Korean vessels in the waters of East China Sea in a sharp violation of UN regulations, South Korean officials say. The oil tanker Lighthouse Winmore was inspected when made a port call at the South Korean port of Yeosu.

Revelations about alleged violations come amid President Donald Trump's charges that China was spotted supplying oil to Pyongyang. China, on Friday (29 December), denied the accusations saying Beijing did not provide North Korea with any oil products.

In the latest development, Seoul's customs authorities say Lighthouse Winmore transferred 600 tonnes of refined petroleum, which was loaded up from Japan, to a North Korean ship Sam Jong 2 on 19 October. The cargo was originally destined to reach Taiwan, instead the vessel distributed the oil in a ship-to-ship transfer not just to the North Korean ship but also to three other vessels.

"The actions taken will be reported to the UNSC [UN Security Council] sanctions committee on North Korea in the future," an official was quoted as saying by South Korea's Yonhap news agency. "This marks a typical case of North Korea shrewdly circumventing UNSC sanctions by using its illegal networks."

Seoul has also shared relevant information from the illegal transaction with American authorities. Officials added the Hong Kong's ship will be kept in their custody for the next six months during when the city-state, a quasi-autonomous region which is heavily under the control of China, can appeal to the UNSC for the release.

North Korea is reeling under intense economic sanctions engineered by the UNSC because of relentless pursuit of nuclear weapons. Despite stinging measures, the country has been finding convoluted ways to pump up money into its coffers in recent years so as to inject that revenue into weapons programmes.

Beijing, a close geopolitical backer and a crucial economic partner of North Korea, denied any knowledge of the latest incident. The country's foreign ministry said they will look into the matter.

"China has launched an investigation following reports that a Chinese ship transferred oil to a North Korean ship in international waters on October 19," foreign ministry spokesperson Hua Chunying told reporters as the allegations surfaced. "The ship has not stopped at a Chinese port since August, and there is no record of it leaving or entering a Chinese port. We are not aware if the ship has visited ports operated by other nations."

Earlier, Chinese ships were spotted transferring oil to North Korean vessels 30 times since October, but Beijing denies those allegations REUTERS/Jo Yong-Hak/File Photo