Frightened Tongans fled to higher ground on Saturday after a massive underwater volcanic eruption – heard in neighbouring countries – triggered tsunami warnings across the South Pacific including on the US west coast.

There were no immediate reports of injuries or the extent of the damage as communications with the small nation remained problematic. 

The US National Weather Service issued tsunami advisories from the bottom of California to the tip of Alaska’s Aleutian islands, predicting waves of up to two feet (60 centimetres), strong rip currents and coastal flooding.

“Move off the beach and out of harbors and marinas in these areas,” it advised.

The Pacific Tsunami Warning Center said “a tsunami is currently being observed” in Hawaii, but said there was “no reported damage and only minor flooding throughout the islands.”

The latest eruption of the Hunga Tonga-Hunga Ha’apai volcano was so intense it was heard as “loud thunder sounds” in Fiji more than 500 miles away.

“A 1.2 metre (over 3.9 feet) tsunami wave has been observed at Nuku’alofa,” Australia’s Bureau of Meteorology said.

The Tonga Meteorological Services said a tsunami warning was in effect for all of the archipelago, and data from the Pacific Tsunami Warning Center showed waves of 2.6 feet had been detected.

Tonga’s King Tupou VI was reported to have been evacuated from the Royal Palace in Nuku’alofa and taken by a police convoy to a villa well away from the coastline.