The wailing siren, which represents an emergency test by Hawaii authorities, sounded for a minute yesterday and marks the first nuclear attack warning siren tested in the state since the Cold War.
The test also follows an announcement by North Korea that it had successfully tested a nuclear-capable intercontinental ballistic missile that can hit “all the US mainland”.
Hawaiian authorities fear the islands are “a likely target”.
Hawaii governor David Ige did admit the possibility of a strike is remote but added that people have to be prepared.
Earlier Hawaii’s Emergency Management Agency administrator Vern Miyagi said: “Hawaii is a likely target because we’re closer to North Korea than most of the continental United States…
“As we track the news and see tests, both missile launches, and nuclear tests, it’s the elephant in the room.
“We can’t ignore it. The people of Hawaii need to know what Hawaii is doing in preparation for this.”
A missile launched from North Korea could strike Hawaii within 20 minutes of launch, it has been reported.
According to nuclear explosion calculator Nuke Map, a North Korean ICBM could kill an estimated 116,410 people and injure at 104,000 others if launched on the Hawaiian capital city of Honolulu.
Its fireball radius could reach up to 0.37miles (0.59km) causing instant death.
Deadly radiation could spread for 1.2miles (1.94km) which has a fatality rate of between 50 and 90 per cent.
However, an estimated 142,600 people would be killed if North Korea’s ICBM detonated in the airspace over Honolulu – the fireball radius would be minimal but the radiation and air blast spread extend as far as 2.3 miles (3.74km).
North Korea released video footage of Kim Jong-un’s latest missile launch on Wednesday after the despot dictator tested world leaders’ patience once again.
Kim Jong-un had seemingly paused his ambition to create an arsenal of deadly weapons, having not fired a rocket since mid-September.
However, on Wednesday morning Pyongyang time, the rogue state’s leader sent a statement to the world by launching a missile higher than ever before.