After a series of strong earthquakes struck Japan, warnings of waves up to a metre high were also issued for parts of North Korea and Russia.
Russian officials issued a tsunami alert for the island of Sakhalin, warning that areas across the island's west coast could be affected by the waves.
In nearby South Korea, the weather agency urged residents in some eastern coastal towns to watch for possible changes in sea levels.
In Japan, warnings of waves up to five metre high have been issued and people have been asked to flee to high land.
Government spokesman Yoshimasa Hayashi told reporters that nuclear plants in the area had not reported any irregularities. But he said it was critical for people in coastal areas to get away from the oncoming tsunami.
“Every minute counts. Please evacuate to a safe area immediately,” he said.