A magnitude-8.7 earthquake in Russia’s Far East early Wednesday prompted tsunami warnings in parts of Japan, Alaska and Hawaii.

Tsunami waves arrived on the eastern coast of Japan following a powerful 8.8. magnitude earthquake off the eastern coast of Russia that also sparked fears of a tsunami in the U.S.

Authorities warned the risk from the 8.8 magnitude quake could last for hours, and millions of people potentially in the path of the waves were initially told to move away from the shore or seek high ground.