A French naval vessel has carried out a surveillance mission targeting North Korea’s illegal ship-to-ship transfers, Japan announced Tuesday, marking the third time in under a month that members of a multilateral sanctions monitoring initiative deployed ships to track smuggling by Pyongyang.

The French frigate FS Prairial took part in efforts to monitor North Korea’s illicit maritime activities in violation of U.N. Security Council resolutions from late October, the Japanese foreign ministry said in a press release.

The foreign ministry did not report when the sanctions monitoring visit to Japan concluded, but the Prairial subsequently sailed to Vietnam and