Some residents along the East Coast received a false tsunami warning on Tuesday morning after a private company sent out an alert following a monthly test by the National Weather Service.
A tweet from the National Weather Service (NWS) in Charleston, South Carolina, said the alert was sent around 8:30 a.m. ET.
"We have been notified that some users received this test message as an actual Tsunami Warning," the NWS tweeted, adding that a tsunami warning was "not in effect."
In a statement to NBC News, the NWS said that a routine test was sent out and that the agency is investigating why it was communicated as an actual tsunami.
"The test message was released by at least one private sector company as an official Tsunami Warning, resulting in widespread reports of tsunami warnings received via phones and other media across the East Coast, Gulf of Mexico, and the Caribbean. We're currently looking into why the test message was communicated as an actual tsunami warning, and will provide more information as soon as we have it," the NWS said.
The agency said their test message "was not disseminated to the public via any communications channels operated by the National Weather Service."
The push notification sent to phones in South Carolina was reportedly sent by the AccuWeather app, according to The Post and Courier of Charleston.
AccuWeather also tweeted that the notification was a test, not an actual warning.
"The National Weather Service Tsunami Warning this morning was a TEST. No Tsunami warning is in effect for the East Coast of the U.S.," the tweet said.
It was not immediately clear how many people received the warning.
Similar reports were also made in New York, Boston, Miami and Houston.
The false alarm is reminiscent of the incorrect alert sent out last month warning of an imminent missile attack in Hawaii.
CORRECTION (Feb. 6, 2018, 10:45 a.m.): An earlier version of this article misstated that the National Weather Service sent out the false tsunami warning. It was sent by a private company after a test by the National Weather Service, not by the weather service itself.