Those last two countries have been involved in a conflict in eastern Ukraine since 2014 and tensions between them rose even more after a confrontation between Russian and Ukrainian ships last month near the Kerch Straight.
It was reportedly detected by an autonomous underwater vehicle which took sonar images of the site and matched them with the dimensions of the lost Japanese warship.
The crew tracked 10 Russian military vessels nearby including this Kilo class submarine, before checking on a U.S. destroyer, the Roosevelt which was also being shadowed by a Russian warship.