Japan has reported to the United Nations suspected ship-to-ship goods transfers involving a North Korean tanker in the East China Sea in violation of U.N. sanctions, the Defense Ministry said Wednesday.

A Maritime Self-Defense Force vessel spotted the North Korean-flagged tanker An San 1 alongside a ship of unknown nationality last Friday in waters around 350 kilometers south-southeast off Shanghai in the East China Sea.

(A North Korean tankar, left, and a ship of unknown nationality in the East China Sea)

Since the two vessels were seen connected with hoses, the Japanese government suspects they conducted ship-to-ship transfers banned by the United Nations, the latest in a series of such illicit transfers involving North Korean and foreign-registered vessels, exposed by the Japanese government.

MSDF ships discovered similar incidents involving North Korean vessels on June 21 and 22 among recent findings.

The An San 1 has been designated as a vessel subject to an asset freeze and banned from entering any foreign port under a U.N. Security Council resolution.

The Japanese Foreign Ministry said it suspects sanctions evasion as the tanker disguised its name as Hope Sea.