SATV Kathmandu, July 30: (Reuters) - A magnitude 8.8 earthquake struck off Russia's Far Eastern Kamchatka Peninsula on Wednesday, damaging buildings and generating a tsunami of up to 4 metres (13 feet) that prompted warnings and evacuations stretching across the Pacific Ocean.

Several people were injured in the remote Russian region, while much of Japan's eastern seaboard - devastated by a powerful earthquake and tsunami in 2011 - was ordered to evacuate.

"Today's earthquake was serious and the strongest in decades of tremors," Kamchatka Governor Vladimir Solodov said in a video posted on the Telegram messaging app.

A tsunami with a height of 3-4 metres (10-13 feet) was recorded in parts of Kamchatka, said Sergei Lebedev, regional minister for emergency situations, urging people to move away from the shoreline.

The U.S. Geological Survey said the earthquake was shallow at a depth of 19.3 km (12 miles), and was centred 119 km (74 miles) east-southeast of Petropavlovsk-Kamchatsky, a city of 165,000. It revised the magnitude up from 8.0 earlier, and reported a strong aftershock of magnitude 6.9 soon after.

Japan's weather agency upgraded its warning, saying it expected tsunami waves of up to 3 metres (10 feet) to reach large areas of its coast.

Tsunami alarms sounded in coastal towns across Japan's Pacific coast with authorities urging people to seek higher ground.

Footage on public broadcaster NHK showed scores of people in the northern island of Hokkaido on the roof of a building, sheltering under tents from the beating sun, as fishing boats left harbours to avoid potential damage from the incoming waves.

Workers evacuated the stricken Fukushima nuclear plant, where a meltdown following the 2011 tsunami caused a radioactive disaster, operator TEPCO said.

Only small waves were recorded and Japan's Chief Cabinet Secretary Yoshimasa Hayashi said there were no injuries or damage reported so far, and no irregularities at any nuclear plants.