A tsunami has hit Japan after a powerful earthquake struck off the east coast of Russia. The first wave was reported to have hit the port of Hanasaki in Hokkaido, in the country's northern region.

NHK World Japan reported that a tsunami of 30 centimeters, or about 1 foot, hit Hokkaido. Tsunami warnings are also in place for other areas of Japan.

Japan's Chief Cabinet Secretary Yoshimasa Hayashi said there were no reports of casualties or damage so far.

The Japan Meteorological Agency earlier warned that a tsunami of more than 3 meters (9.8 feet) high could hit parts of the country, including northern Hokkaido, from 10 a.m. local time on Wednesday, with the possibility of it gradually spreading south.

An 8.8-magnitude earthquake struck off the eastern coast of Russia at 8:25 a.m. local time today, the United States Geological Survey (USGS) said.

The USGS initially reported that the magnitude of the earthquake was 8 on the Richter scale. It was later revised twice to 8.8.

There were no immediate reports of casualties in Russia after the powerful earthquake, which is being described as the most powerful to hit the country's Kamchatka Peninsula in decades. There were no initial reports of casualties there either.

However, after a tsunami warning was issued, people were ordered to evacuate a small town in the local Sakhalin region.

In addition to Japan, a tsunami warning has been issued for Taiwan and the US state of Hawaii.