People across the US state of Hawaii received a text alert this morning, warning of an impending ballistic missile threat.
It was declared a false alarm 20 minutes later, but not before panic started to spread.
The message said "Ballistic missile threat inbound to Hawaii. Seek immediate shelter. This is not a drill." The warning went out to television and radio as well as cell phones.
Governor of Hawaii David Ige has apologised and said human error caused the alert to go out.
"This should not have happened, we are investigating the sequence of events that occurred. An error was made in emergency management ...it was a procedure that occurs at the change of shift where they make sure the system is working and an employee pushed the wrong button."
The New Zealand golfer Danny Lee, who is in Hawaii for a tournament, tweeted that he had received the alert, and later the follow up text that there was no missile threat or danger.
PGA official Will Haskett was getting ready to drive to the course in Honolulu and told RNZ there was a great deal of concern by everyone at his hotel.
"There were sort of various levels of panic so you had people that were scrambling to get in their cars and try and get out and there were people that were running towards the parking garage to try and seek shelter underground," he said.
"And that lasted for about 20 minutes until finally there were the various tweets and alerts and things to say that it was actually a false alarm so for a period of about 20 minutes there it was a pretty heightened sense of fear and confusion."
Will Haskett said the error was bound to cause some issues for local government officials.
In December, Hawaii tested its nuclear warning siren for the first time since the end of the Cold War.
It came amid a growing threat from North Korea's missile and nuclear programme. Hawaii is the closest state to North Korea.
In September Pyongyang carried out its sixth nuclear test.
Last month, the Star-Advertiser also reported that a missile launched from North Korea could strike Hawaii within 20 minutes of launch.