U.S. and South Korean special forces recently practiced boarding and seizing foreign vessels as part of an international naval exercise, a move that one expert said signals Seoul’s stronger stance against North Korea sanctions evasion.

According to the U.S. Indo-Pacific Command, the elite fighting units conducted Visit, Board, Search and Seizure (VBSS) training in the opening days of this year’s annual Rim of the Pacific (RIMPAC) exercise, which kicked off on June 29 and involves over two dozen countries and tens of thousands of military personnel.