Ms Walters comments contradict the regret displayed by Hawaii Governor David Ige, who apologised for the false alert that left locals terrified.
She said: “The President has been briefed on the state of Hawaii’s emergency management exercise. This was purely a state exercise.”
Earlier, Mr Ige had labelled the day one that “most of us will never forget” that resulted in Hawaiians thinking their “worst nightmares might actually be happening” in a news conference.
He stated: “Today is a day that most of us will never forget, a day that many in our community thought our worst nightmares might actually be happening, a day when many frantically tried to think about the things they would do if a ballistic missile launch would happen.
“I know firsthand that what happened today was totally unacceptable and many in our community were deeply affected by this and I’m sorry for that pain and confusion anyone might have experienced.
“I’m too very angry and disappointed this happened.”
The Governor added that routine alerts in the country would be suspended until “appropriate changes” were made.
He declared: “Routine activities will be suspended until we can implement appropriate changes.
“We have already implemented some of the changes to ensure that more than one person is involved with that.
“We definitely learned that some of the notifications, some of the sirens did not work and we need to understand what that is.
“On a going forward basis, we do intend to continue the monthly siren tests and other tests as we have done in the past.
“We believe that it is imperative that we continue to exercise the alert system.
“We recognise that this false alarm is a terrible thing to happen and we have implemented changes already to ensure that it doesn’t happen again.
“We will further refine the processes as we go forward to make sure that we can put in better safeguards to prohibit this from happening.”
The person responsible for issuing the alert was identified after Hawaii Emergency Management Agency Administrator Vern Miyagi admitted it was his “responsibility” and declared the body will work to ensure it “never happens again”.
He went on: “It’s my responsibility so this would be my fault.”
An automated warning telling Hawaiians to “seek immediate shelter” was sent out to phones yesterday, prompting some to scramble for cover in storm drains and others to huddle in basements.
The message read: “Emergency alert.
“Ballistic missile threat inbound to Hawaii. Seek immediate shelter. This is not a drill.”
A second message delivered nearly 40 minutes later, said there was no threat or danger.