A magnitude 6.2 earthquake has occurred in eastern Russia near the border with China and North Korea.
The US Geological Survey said it hit shortly after midnight local time, but there have been no reports of casualties or damage.
The quake was centred southwest of Vladivostok, about 9km from the border town of Zarubino, at a depth of 561kms.
The South Korean Defense Ministry has confirmed the quake was a result of natural causes and not a nuclear test.
There was a magnitude 6.1 quake in the far east of Russia last month and a 6.9 quake occurred in February. Neither caused significant damage.