SAN FRANCISCO, Jan. 23 (Xinhua) -- A tsunami warning has been canceled for all Alaska following no reports of significant waves and damage from a 7.9-magnitude quake that struck the U.S. most northwest state early Tuesday, the U.S. National Tsunami Warning Center tweeted.

"CANCELLATION: M7.9 175mi SE Kodiak City, Alaska 0032AKST Jan 23: Check with local officials for all clear," the center said in a tweet Tuesday.

Alaska's major news outlet, the Anchorage News Daily, said "all Alaska warnings, alerts and advisories were canceled just after 4:00 a.m. (05:00 a.m. GMT), and there were no reports of significant waves or damage."

The Tsunami warning was issued after the major earthquake, which was centered 181 miles (about 290 kilometers) southeast of Kodiak in the Gulf of Alaska, struck at 12:31 a.m. local time (01:31 a.m. GMT).

The quake was measured 15.5 miles (about 25 kilometers) deep, the U.S. Geological Survey (USGS) said.

The magnitude was initially reported to be about 6 miles (9 kilometers) deep and 8.2-magnitude but was later downgraded to 7.9.

The earthquake triggered a tsunami warning not only for Alaska but all the west coast of mainland United States including coastal California.

In San Francisco, a major tourist city in the U.S. west coast, the tsunami warning was also canceled, but the city's emergency management department urged residents to avoid shorelines, marinas, harbors until late Tuesday afternoon, local TV KPIX 5 said in a tweet.

It quoted emergency management officials as saying that some shoreline areas, marinas and harbors may have dangerous and unpredictable currents.