Six Russian sailors died in a fire on a cargo ship in northern Japan, dpa quoted news reports as saying. The fire apparently broke out late Wednesday in the port of Wakkanai, on the northern tip of the northern island of Hokkaido, several Japanese media sources reported. The cause of the fire on the Cambodia-flagged freighter was not yet clear. Three Russian crew members were rescued with mild smoke poisoning and burns. The remaining crew from Russia and Ukraine were not hurt. Rescue work was hampered by the vessel's small rooms and interior fittings, reports said. The rescue teams found the bodies of the six missing sailors in the wreckage of the ship, which was two-thirds burnt.