The U.K. recently deployed a warship to the waters around Japan to monitor North Korea’s illicit maritime activities to circumvent U.N. sanctions, the British navy announced on Monday.

The HMS Richmond carried out sanctions surveillance operations including tracking DPRK ship-to-ship transfers of contraband from early to mid-September, the Royal Navy said in a press release.

The British surveillance operation came as part of an ongoing Indo-Pacific tour by the U.K. Carrier Strike Group, which is led by the aircraft carrier HMS Prince of Wales.

The Type 23 frigate paid a visit to Busanin South Korea last month before