Hawaii to test warning systems for natural disasters - and nuclear attack
Hawaii is dusting off a relic not heard on the islands since the end of the Cold War - the siren designed to alert residents of an impending nuclear attack.
The warning sirens are tested every month for natural disasters, but Friday's test will have an added tone.
It comes days after North Korea said it launched a nuclear-capable intercontinental ballistic missile which was "significantly more" powerful than previous tests.
"We believe that it is imperative that we be prepared for every disaster, and in today's world, that includes a nuclear attack," Hawaii governor David Ige said, adding that the possibility is remote.
Mr Ige said the new test will ensure the public knows what they should do in case of an imminent attack.
If a missile is launched, residents and tourists would have less than 20 minutes to take shelter, officials said.
"There needs to be different action taken should there be a nuclear attack than what is expected for a hurricane or tsunami," the governor said.
The attack warning with a wailing sound will be tested after a test of the long, steady siren for tsunamis and other events that people in Hawaii have grown accustomed to.
Vern Miyagi, administrator for Hawaii Emergency Management Agency, said the state delayed the test for a month to let people know it would be happening.
Hawaii turned to public service announcements on TV and radio, town hall meetings and information on agency websites.
"The public can handle it. They're not going to panic," Mr Miyagi said.
Earlier this week, North Korea fired a powerful nuclear-capable intercontinental ballistic missile it calls the Hwasong-15, leading analysts to conclude the nation has made a jump in its missile capability.
The weapon would have a range of more than 8,100 miles (13,000 kilometres), easily reaching the US mainland.
Hawaii is the closest state to North Korea, and its large military presence could make it more of a target.
The island of Oahu is home to the US Pacific Command, the military's headquarters for the Asia-Pacific region.
It also hosts dozens of Navy ships at Pearl Harbour and is a key base for the Air Force, Army and Marine Corps.
Miyagi has previously said a nuclear strike on Hawaii would result in thousands of deaths, thermal radiation, severe damage to critical infrastructure, widespread fires and other chaos.
"I think it's responsible to do this," Honolulu Mayor Kirk Caldwell said of the tests, though adding the chances of an attack are slim.
The tests will continue on the first day of every month. If the siren sounds because an attack is imminent, residents and tourists should get inside and stay tuned for further instructions, officials said.