Residents in the state received emergency alerts on their mobile phones advising them to "seek immediate shelter" from an inbound ballistic missile.
"Hawaii - this is a false alarm", wrote Democratic Representative Tulsi Gabbard on Twitter.
Hawaiian officials, as well as the U.S. Pacific Command, followed suit but not until almost 40 minutes later. "It was a false alarm based on a human error".
"The President has been briefed on the state of Hawaii's emergency management exercise". Brian Schatz (D-HI) said that the mistake was "totally inexcusable".
"We did make the determination that it was a false alarm".
"Finally we got that alert saying it's a false alarm".
"State Warning Point has issued a Missile Alert in ERROR!"
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She said she passed out during the incident, but didn't report it for fear of losing her job. "I had no idea this is happening during my tenure or once I left", she lasted.
Hospital patients were moved, children were ushered into storm drains for cover and many sent panicked messages to loved ones.
North Korean President Kim Jong-un has threatened to unleash his country's growing missile weapon capability against USA states or the U.S. territory of Guam, prompting President Donald Trump to threaten tough actions against Pyongyang.
Agency spokesman Richard Repoza confirmed it was a false alarm and the agency is trying to determine what happened.
'There is nothing more important to Hawai'i than professionalizing and fool-proofing this process'.
The U.S. Federal Communications Commission announced that it was initiating a full probe into the incident.
"What happened was. during shift changes (with) outgoing and incoming staff, somebody selected the wrong item on a computer". The whole state was terrified.
Though administrator Vern Miyagi said at a press conference that an unnamed longtime employee made the error, Rapoza told USA TODAY, "We're not pointing fingers at an individual".
The state began testing its nuclear warning system in December, CNN reported.
North Korea has tested a volley of ballistic missiles over the last few years, and has repeatedly threatened the USA with nuclear conflict.