A tsunami alert has been issued after a 7.9-magnitude earthquake was recorded off the coast of Alaska in the US.

It hit some 300 km south-east of Kodiak at a depth of 10 km at the US Geological Survey said.

The US National Weather Service said a warning was in effect for the coasts of British Columbia and Alaska, while the US west coast is on tsunami watch.

Officials in Anchorage warned coastal areas, saying there was "extraordinary threat to life or property".

The alert told people to seek refuge on higher ground in affected areas.

The NWS Pacific Tsunami Warning Center said that, based on the preliminary earthquake parameters, "widespread hazardous tsunami waves were possible".

Hawaii has also been placed on tsunami watch.

One Twitter user is reporting hearing tsunami sirens in Kodiak.