Tokyo has lodged a protest with Pyongyang after a vessel allegedly threatened a fisheries patrol boat in Japan's exclusive economic zone, government sources said Wednesday.
The Fisheries Agency crew said the vessel, believed to be from North Korea, trained a gun on their patrol boat and pursued it in the Sea of Japan last Friday, according to the sources.
The boat was followed for more than 10 minutes, but the gun was not confirmed to have been fired, the sources said.
The incident took place in area for squid-fishing where North Korean ships are believed to be illegally fishing.