Correction: This article has been amended to correctly identify the Yu Jong 2, not the Yu Jong.

Six North Korean ships recently rebroadcast their locations after a three-year absence from international trackers, the NK Pro Ship Tracker shows.

Their reappearances following the lifting of COVID-19 restrictions at North Korean ports may indicate new tasking and a trend of previously sanctioned ships re-appearing after a predetermined time offline.

Three of the ships are previously sanctioned tankers that broadcast their Automatic Identification System (AIS) signals from the narrow Korean Strait, the busy sea lane bridging the