Communities along a 1,126-kilometre stretch of Alaska's southern coast ordered residents to higher ground after a powerful offshore earthquake Wednesday, but officials quickly downgraded and then cancelled a tsunami warning for the region.

A major earthquake with a preliminary magnitude of 7.3 initially triggered a tsunami warning for the southern Alaska Peninsula. It was later downgraded to an advisory.

A tsunami warning was issued for parts of the Alaska coastline after a major, 7.3-magnitude earthquake struck 87 kilometres south of Sand Point. The alert has since been cancelled