Tsunami warnings have been issued in Japan, Alaska, California and Hawaii after amagnitude 8.7 earthquake struck in Russia's far east.
Damage and evacuations were reported in the Russian regions nearest the quake's epicentre on the Kamchatka Peninsula.
The Pacific Tsunami Warning Centre said waves of up to three metres above tide level were possible along some coastal areas of Hawaii, Chile, Japan and the Solomon Islands.
Waves of more than 3 metres were possible along some coastal areas of Russia and Ecuador.
Japan's meteorological agency issued a tsunami alert for Japan's Pacific coast, saying waves up to 3 metres could arrive along the northern Japanese coasts less than half an hour after the alert.
The Pacific Tsunami Warning Centre said a tsunami had been generated by the quake that could cause damage along the coastlines of all the Hawaiian islands.
"Urgent action should be taken to protect lives and property," the warning stated. The first waves were expected around 7pm Tuesday local time.
Kamchatka Governor Vladimir Solodov said wave heights of between three metres and four metres had been recorded in parts of the region.
"Today's earthquake was serious and the strongest in decades of tremors," Solodov said in a video posted on the Telegram messaging app. He said so far there were no injuries, but a kindergarten was damaged.
The quake at 8.25 am Japan time had a preliminary magnitude of 8.0, Japan and US seismologists said.
Japan and the US Geological Survey later updated their measurements to 8.7 magnitude and the USGS said the quake occurred at a depth of 19.3 kilometres.
The quake was about 250 kilometres (160 miles) away from Hokkaido, the northernmost of Japan's four big islands, and was felt only slightly, according to Japan's NHK television.
Russia's Tass news agency reported from the biggest city near the epicentre, Petropavlovsk-Kamchatsky, that many people ran out into the street without shoes or outerwear.
Cabinets toppled inside homes, mirrors were broken, cars swayed in the street and balconies on buildings shook noticeably.
Tass also reported power outages and mobile phone service failures in the capital of the Kamchatka region.
Tass also quoted a local Russian official as saying residents on Sakhalin Island were being evacuated and emergency services were working at full capacity.
The National Tsunami Warning Centre, based in Alaska, issued a tsunami warning for parts of the Alaska Aleutian Islands, and a watch for portions of the West Coast, including California, Oregon, and Washington, and Hawaii.
The advisory also includes a vast swath of Alaska's coastline, including parts of the panhandle.
Earlier in July, five powerful quakes – the largest with a magnitude of 7.4 – struck in the sea near Kamchatka.
The largest quake was at a depth of 20 kilometres and was 144 kilometres east of the city of Petropavlovsk-Kamchatsky, which has a population of 180,000.
