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, Reuters reports.
With earthquakes centered deep underground, sometimes those close to the epicenter don't feel it while people further away notice some shaking, said the duty officer at the Seismological Bureau of Yanbian Korean Autonomous Prefecture in northeast China's Jilin province. He refused to give his name as is common among Chinese officials.
The Korea Earthquake Research Center said there was no damage in North or South Korea and that quakes occur in that region about once a year.
The USGS said the epicenter was on the Russian coast along the Sea of Japan, 61 miles (98 kilometers) west-southwest of Vladivostok, about 70 miles (110 kilometers) east of China's Yanji city in Jilin province, The Associated Press reports.
More than 3,500 people were detained during unprecedented mass protests that swept across all of Russia in support of Alexey Navalny on January 23