Local radio on the Alaskan island of Kodiak, close to the epicenter, urged listeners to move away from coastal areas.

"This is a tsunami warning. this is not a drill. Please get out to higher ground," said the announcer on KMXT public radio. "If you are on the flats, get up on one of the hills Just go high."

There were no immediate reports of damage or injury.

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The quake, initially measured at magnitude 8.2, hit around 250 km (160 miles) southeast of Chiniak, Alaska at a depth of 25 km at 0931 GMT, the U.S. Geological Survey said.

"If you are located in this coastal area, move inland to higher ground. Tsunami warnings mean that a tsunami with significant inundation is possible or is already occurring," the Anchorage Office of Emergency Management said in a warning for Alaska and British Columbia.

A tsunami watch for the entire U.S. west coast and Hawaii were issued.

"Based on all available data a tsunami may have been generated by this earthquake that could be destructive on coastal areas even far from the epicenter," the Pacific Tsunami Warning Center said.

If a tsunami is generated, it could reach Hawaii by 4:23 a.m. (14:23 GMT) at the earliest, it added.

Japan's meteorological agency said it was monitoring the situation but did not issue a tsunami alert.

REUTERS