Residents of Hawaii have been mistakenly alerted via their phones a missile was inbound.
"BALLISTIC MISSILE THREAT INBOUND TO HAWAII," it reads in all-caps. "SEEK IMMEDIATE SHELTER. THIS IS NOT A DRILL."
CNN producer Amanda Golden posted a screenshot of the alert on Twitter.
Others confirmed they had also received the alert, but some noted no sirens were sounding and there was nothing on TV.
"We got the alert and were out for a walk, and one of the locals was behind us and she told us to come with her, and then we went into a house," Dunedin woman Leah Hay told Newshub by phone from Honolulu.
"There was nothing on the news or anything, and no other alerts. Everybody was a bit stressed - they didn't know what was going on."
Congresswoman Tulsi Gabbard soon confirmed with officials it was a false alarm, sent out in error.
"HAWAII - THIS IS A FALSE ALARM," she wrote on Twitter, also in all-caps. "THERE IS NO INCOMING MISSILE TO HAWAII. I HAVE CONFIRMED WITH OFFICIALS THERE IS NO INCOMING MISSILE."
The Hawaii Emergency Management Agency confirmed it too, saying it was in fact part of a drill.
A spokesperson for the North American Aerospace Defense Command told media it was "possibly a hack" or a "very sick joke".
Ms Hay told Newshub once the second alert arrived confirming there was no missile, everyone calmed down.
"Everybody was a bit on edge for a while."
New Zealander internet entrepreneur Seeby Woodhouse is also in Hawaii, and said there was "mayhem" following the alert.
"Is this just a strategy to create fear in the general populace?" he wondered.
Kiwi golfer Danny Lee, also in Hawaii, was relieved to discover it was a false alarm.
Sports journalist Timothy Burke was watching a football game when an alert appeared on television, with a harsh tone and monotone voice warning viewers to take shelter.
Hawaii's Governor David Ige said he was "thankful" it was a false alarm, saying it appears to have happened when someone "pushed the wrong button" during a change of shift.
In October, New Zealand's Civil Defence organisation came under fire for accidentally sending out a test message at 2am.