The alert, delivered through text messages and Facebook, read: "Real World Noncombatant evacuation operation order issued. All DoD family members and non-emergency essential DoD civilians on the Korean Peninsula an evacuation order has been issued."
The hoax was shut down by officials within an hour after being reported on Thursday, and US Forces Korea quickly issued their own statement saying "USFK did not issue this message."
The statement urged anyone who was sent the order to "not click any links or open any attachments included in the correspondence," adding that all families associated with the Defense Department should first "confirm any evacuation-related communications with their service members and unit non-combatants evacuation representatives."
According to Stars and Stripes, the fake notice would have set off a mass evacuation of 28,500 service members and their families.
Though the military does initiate biannual non-combatant evacuation exercises, such an order has not been issued in earnest since the Korean War was stopped by armistice 64 years ago, the outlet added.
This false alarm follows Trump's Tuesday speech at the United Nations General Assembly where 45 said the US would "totally destroy" North Korea if Pyongyang forced the US' hand.