Washington: The state worker in Hawaii who sent a false wireless alert warning of an inbound ballistic missile on January 13 issued the message intentionally, thinking the state faced an actual threat, the Federal Communications Commission said Tuesday.

The mistake, which touched off widespread confusion and panic in Hawaii, occurred when an emergency management services worker on the day shift misinterpreted testing instructions from a midnight shift supervisor, the commission said. Believing the instructions were for a real emergency, the day-shift worker sent the live alert to the mobile phones of all Hawaii residents and visitors to the state.

A smartphone screen capture shows a false incoming ballistic missile emergency alert sent from the Hawaii Emergency Management Agency system on Saturday. AP

Officials had previously described the episode as an accident. Shortly after it happened, Governor David Y. Ige of Hawaii blamed the false warning on a state employee who "pressed the wrong button." State officials are scheduled to discuss the findings of their own investigation on Tuesday afternoon.

Although other emergency management officials in Hawaii knew that the state was supposed to be conducting an internal drill at the time, the employee who sent the alert, who has not been publicly identified, told the commission in a written statement that he or she believed it was an actual emergency.

The employee then chose from options in a drop-down menu that included test and real alerts. When prompted with the question "Are you sure you want to send this alert?," the employee clicked "yes," according to the commission.

The commission faulted the state for lacking measures to prevent the human error and, once it occurred, for taking 38 minutes to correct it.

Vern Miyagi, Administrator, HEMA, left, and Hawaii Governor David Ige addressed the media during a press conference at the Hawaii Emergency Management Centre following the false alarm issued of a missile launch on Hawaii. AP

Hawaii "didn't have reasonable safeguards in place," Ajit Pai, the commission chairman, said.

"It is astounding that no one was hurt," said Mike O'Reilly, a Republican commissioner.

The mistake has stoked calls by lawmakers and regulators to improve wireless emergency alerts, which are slowly being updated to include longer messages and Spanish language versions.

The episode revealed huge differences in how the alerts are sent. In places like Houston, Chicago and New York City, tests and real alerts aren't put together in the same drop down menus and sending an alert requires at least one other person's approval.

Some lawmakers have proposed that only members of the Department of Defence or Department of Homeland Security should be able to send a warning about missile threats.

New York Times