An earthquake of magnitude 6.7 hit near the China-Russia border on Thursday, but its epicenter was extremely deep and there were no immediate reports of casualties or damage.
The quake, which occurred at 0113 GMT, was centered midway between the Russian city of Vladivostok and Chongjin, North Korea's third largest city. It struck at a depth of 563 km (350 miles), the U.S. Geological Survey said.
The Pacific Tsunami Warning Center put the coordinates at 42.7 north and 130.9 east. It said there was no danger of a tsunami.
Early estimates put the magnitude at 6.9. The USGS later put the figure at 6.7, a powerful quake but one with effects on the surface likely to be minimized by the extreme depth.
"As far as we know, there have been no reports of damage," an official at China's national seismological bureau told Reuters.
"There have been no reports of any damage here. Everything is calm," a spokesman for Russia's Emergencies Ministry in the Far East city of Vladivostok said by telephone.
"Since the earthquake was 560 km underground, there shouldn't have been much damage," Ham Young-mo at South Korea's National Earthquake Center said.
North Korea's official news agency carried no immediate reports on the quake.
