A 6.6 magnitude earthquake in Anchorage has prompted a Tsunami warning.
As the earthquake hit, people ran out of buildings to seek shelter under office desks.
The US Geological Survey says the earthquake was centred around seven miles (12km) north of Alaska’s largest city, Anchorage.
People went back inside buildings after the earthquake but a smaller aftershock later sent them running back into the streets again.
The National Tsunami Warning Centre issued a tsunami warning for coastal zones of southern Alaska following the quake in downtown Anchorage.
Police in Alaska’s Kodiak island community – about 200 miles (321km) south of Anchorage – have told residents to head to higher ground amid the tsunami threat.
A lawyer working and living in Anchorage, Hank Graper, said he was driving when the quake struck.
He realised it was an earthquake after he saw traffic poles swaying and called it the most “violent” quake he’s experience in his 20 years in the city.
Pictures posted to social media sites showed damage that included collapsed ceiling tiles at an Anchorage high school and buckled roadway pavement in places.
One photo shows a newsroom based in the city that felt the blow of the earthquake.
Another showed a car in the middle of a collapsed road.
Cereal boxes and packages of batteries littered the floor of a grocery store and picture frames and mirrors were knocked from living room walls.
Alaska averages 40,000 earthquakes per year, with more large quakes than the other 49 states combined.
Southern Alaska has a high risk of earthquakes due to tectonic plates sliding past each other under the region.
On 27 March 1964, Alaska was hit by a magnitude 9.2 earthquake, the strongest recorded in US history.
It centred about 75 miles (120km) east of Anchorage and lasted about four-and-a-half minutes. The tsunami it triggered claimed about 130 lives.