A Chinese cargo ship with no voyage history, no international registration and a brand new radio identity has sailed into North Korean waters in its first known trip, NK Pro analysis of ship-tracking data shows.

The unusual voyage by the ship broadcasting as the China-flagged Lei Shan 5 comes as Pyongyang has moved to bolster its merchant fleet in recent months, raising the possibility that North Korea has acquired the vessel.

According to maritime database MarineTraffic, the Lei Shan 5 departed from near Shidao on July 25 with its stated destination as Taicang, a Chinese city 400 miles (640 km