An emergency alert was mistakenly broadcast to Guam residents amid fears of missile strikes against the Pacific island by North Korea.
The alert went out on a radio station just after midnight on Tuesday in Guam and said a "civil danger warning" had been issued for the island.
The Guam Homeland Security office blamed it on human error and said the mistake will not occur again.
Guam authorities say they remain in close contact with the US military and have not elevated the threat level on the island.
North Korea's military presented leader Kim Jong Un with plans to launch missiles into waters near Guam.