Tsunami warning issued for USA after underwater volcano erupts in Tonga

The National Weather Service (NWS) said tsunami advisories were in effect for Alaska and the west coast, forcing some beaches and piers to close in California.

NWS wrote: "Impacts may include inundation of low lying areas, coastal flooding, and strong rip currents."

Japan has also warned of waves as high as three metres, whilst authorities in Fiji also issued a warning telling people to avoid the shoreline due to strong currents and dangerous waves.

It comes after the Hunga Tonga volcano had a "violent" eruption with the Pacific country's meteorological service issuing an alert for the entire nation, which spans more than 100 islands.

Videos on social media show people rushing to get to safety, the sea engulfing buildings and large waves crashing into the shore.

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Many parts of Tonga are experiencing a near-total blackout of power, phone lines and internet services.

The extent of any injuries or damage is still unclear.

King Tupou VI was evacuated from his palace, near the shore, by a convoy of military and police personnel, the Islands Business news site said.

Read more: Tonga: Rush to safety after undersea volcano eruption triggers tsunami warning

Earlier, the Matangi Tonga news site reported that scientists observed massive explosions, thunder and lightning near the volcano after it started erupting early on Friday.

The site said satellite images showed a three mile-wide plume of ash, steam and gas rising 12 miles into the air.

More than 1,400 miles away in New Zealand, officials warned of storm surges from the eruption.

The National Emergency Management Agency said some parts could expect "strong and unusual currents and unpredictable surges at the shore following a large volcanic eruption".

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The volcano is about 40 miles north of the Tongan capital Nuku'alofa.

In late 2014 and early 2015, a series of eruptions in the area created a small new island and disrupted international air travel to the Pacific archipelago for several days.