The US government has criticised Hawaii's handling of a false alert of a missile attack earlier this month, saying an employee mistook a test drill for an actual attack.
The false alarm, which went uncorrected for 38 minutes after being transmitted to mobile phones and broadcast stations, caused widespread panic across the US state.
The US Federal Communications Commission blamed the error in part on a miscommunication and a lack of supervision of the test drill by the Hawaii Emergency Management Agency.
The employee who transmitted the alert said in a written statement that he or she believed it was an actual alert, rather than a drill.
A recording mimicking a call from US Pacific Command was played.
The employee had clicked yes in response to a prompt that read: "Are you sure that you want to send this Alert?" the FCC said in a presentation.
The drill recording did not follow the standard script for a practice and included the phrase "this is not a drill".
It ended with the phrase "exercise, exercise, exercise".
The officer who issued the alert heard "this is not a drill" but did not hear "exercise, exercise, exercise," he told Hawaii in a written statement to the FCC.
Other employees told the FCC they heard "exercise", FCC lawyer James Wiley said during the presentation.
Hawaii's governor David Ige has said the employee pressed the wrong button by mistake.