The United States Geological Survey has said a magnitude 7.3 earthquake has hit the waters off of far eastern Russia.
There were no immediate reports of damage or injuries and no tsunami was generated.
The quake hit just before 1pm local time on Tuesday. It was centred in the Pacific Ocean, an estimated 160km east of Poronaysk, Russia, at a depth of more than 625km.
In Japan, the Meteorological Agency reported that there was no risk of a tsunami from the quake. Its readings showed the quake was mildly felt on the northern Japanese island of Hokkaido and in the northeastern section of Honshu, Japan's main island.