Japan has discovered another North Korean tanker it suspects of transferring goods with a vessel in defiance of U.N. Security Council resolutions, the Foreign Ministry said on Tuesday.

It was the fourth time Tokyo has suspected such an illegal transfer in recent weeks and comes as the Trump administration and key Asian allies prepare to expand interceptions of ships suspected of violating sanctions on North Korea.

North Korea last year conducted dozens of missile launches and its sixth and largest nuclear test as it pursues its goal of developing a nuclear armed missile capable of reaching the United States, triggering deeper U.N. Security Council sanctions.