A push alert that warned of an incoming ballistic missile to Hawaii sent residents into a full-blown panic Saturday until state emergency officials said it was a mistake.

The emergency alert, which was sent to cellphones said in all caps, "Ballistic missile threat inbound to Hawaii. Seek immediate shelter. This is not a drill." The alert also aired on television and radio.

Hawaiian Congresswoman Tulsi Gabbard tweeted about it, warning it was a false alarm.

The Hawaii Emergency Management Agency also sent a tweet about 10 minutes after the push alert, saying there was no threat.

But media reports said about 38 minutes passed before a new push alert — stating that the original alert was a false alarm — went to cellphones.

The alert was transmitted mistakenly by state authorities due to human error, Hawaii's governor and emergency management chief said.

Governor David Ige, a Democrat, said on CNN the alert was sent out by mistake during a shift change at the Hawaii Emergency Management Agency. Ige told reporters someone at the state emergency management agency pushed the "wrong button" during a shift change.

Vern Miyagi, the agency's administrator, said in comments also aired on CNN, "It was an inadvertent mistake. The change of shift is about three people. That should have been caught. ... It should not have happened."

Congress Gabbard

Hawaiian Congresswoman Tulsi Gabbard tweeted about the alert, warning it was a false alarm. (J. Scott Applewhite/Associated Press)

Miyagi said there was a "check list" that should have been followed. He said, "I think we have the process in place. It's an matter of executing the process. I think it's human error."

Hawaii Sen. Brian Schatz said the false alarm was "totally inexcusable." 

Schatz went on his Twitter account after emergency management officials confirmed the push alert about an incoming missile Saturday was a mistake, calling for accountability and an alert process that is foolproof. 

The alert caused panic on the island and across social media.

Many people were still in bed when the alarm was triggered, including Canadian Elain Evans, a Vancouver resident who is staying with friends in a home north of Honolulu, on Oahu. 

Canadians in Hawaii tell their stories

She said she and her family gathered essentials and went to hide in a corner of the basement where they'd seen the dog take refuge during New Years Eve fireworks.

"We figured the dog would know best," Evans said. "We hid down there and tried to make phone calls ... the system was jammed with a weird message."

Evans and her family are scheduled to leave Hawaii for Vancouver Saturday evening.

"Two degrees have never felt so good as it will tomorrow morning when we get off that plane," she said.

Canadian Marissa Sciera, on her honeymoon in Maui, described loud alarms coming over the speakers in her hotel alerting her to the threat and advising people not to panic and to stay in their rooms. She and her husband were on the 12th floor of the hotel.

"Terrifying, terrifying. I was shaking and I was way calmer than my husband. It was horrifying," said the resident of Prince George, B.C. 

Canadians with relatives in Hawaii were also affected by the alert.

Rebecca MacLeod's daughter, Jessica, is in Hawaii on her honeymoon. MacLeod, who lives in Mount Uniacke, N.S., said her daughter texted her when the alert came through.

Trying to make sense of it

"She sent three texts and the screenshot," said MacLeod. "It was just, 'Mom, apparently there's a missile on its way to Hawaii, we have to seek shelter. I'm not sure what that means, but I love you and I'll be in touch as soon as I can.'

"I had to make sense of what exactly she was saying. A missile!" said MacLeod. 

MacLeod said she started looking for news articles online to find out more information. She eventually saw the tweet from Hawaiian Congresswoman Tulsi Gabbard that said the alert was a false alarm.

MacLeod said the experience was a terrifying 15 to 20 minutes.

"When an emergency measures organization puts out something that says 'This is not a drill' ...  I'm not going to lie, I was a hot mess. I'm still choked up."

MacLeod said she was able to text her daughter after the false alarm message.

"I went into Mom mode again and [said] 'Try to relax' ... but I'm a little bit upset with the person who sent out that message," MacLeod said.

U.S. President Donald Trump was silent about the false alarm, prompting Gabbard to criticize his lack of action and accuse him of failing to take the threat to Hawaiians seriously.

The threat came amid fears of growing nuclear capability in North Korea. President Kim Jong-un has threatened to unleash his country's missile weapons against the U.S. territory of Guam or other U.S. states, prompting President Trump to threaten tough actions against Pyongyang, including "fire and fury."

White House Deputy Press Secretary Lindsay Walters confirmed in a statement that Trump, who is spending the weekend at his estate in Palm Beach, Fla., knew about the alarm.

"The president has been briefed on the state of Hawaii's emergency management exercise. This was purely a state exercise."

In a tweet Saturday afternoon, Chairman of the Federal Communications Commission Ajit Pai said the commission would launch "a full investigation into the false emergency alert that was sent to residents of Hawaii."

With files from CBC's Ash Kelly, CBC News Nova Scotia, Reuters