An earthquake of 7.3 magnitude on the Richter scale struck off the coast of the US state of Alaska on Wednesday (local time), prompting the authorities to issue a tsunami warning, the United States Geological Survey said.

The earthquake occurred at around 12.37 local time (2037GMT) and its epicenter was located at 87 kilometers south of the island town of Sand Point, USGS said. The depth of the epicenter was 20.1 kilometers.

The authorities have issued a tsunami warning for South Alaska and the Alaska Peninsula after the massive earthquake, news agency AFP reported.

“A tsunami has been confirmed and some impacts are expected," said the National Tsunami Warning Center in Palmer, Alaska.

The warning was put out for “South Alaska And the Alaska Peninsula, Pacific coasts from Kennedy Entrance, Alaska (40 miles SW of Homer) to Unimak Pass, Alaska (80 miles NE of Unalaska)," it added.

The US Tsunami Warning Center issued a warning for a large part of Alaska’s coastline — from about 40 miles southwest of Homer to Unimak Pass, covering nearly 700 miles. This included several coastal towns like Kodiak, an important local center with around 5,200 people.