AMERICANS ACROSS THE country on Wednesday will receive the first-ever presidential text alert on their mobile devices.

However, the alert won't be from President Donald Trump himself, a Federal Emergency Management Agency official told CNN. The message will come to phones around 2:18 p.m. eastern time and is the first nationwide test of a system built by cell phone companies and the government that will be sent to almost all cellphones in the U.S., according to the official.

"The president will not originate this alert, say, from his mobile device," the official said. "You would not have a situation where any sitting president would wake up one morning and attempt to send a particular message."

A presidential alert will be limited to certain events that threaten public safety, such as "coordinated attacks on our major cities" or "some other type of public peril that is ongoing in the country at the time," CNN reported.

The message will read: "THIS IS A TEST of the National Wireless Emergency Alert System. No action is needed."

A similar message will be broadcast over television and radio stations a few minutes later. This type of alert will look and sound like other emergency alerts, such as severe weather alerts. However, while users can opt-out or disable other emergency notifications, people cannot opt-out of presidential text alerts.

During a real emergency, a FEMA official would gather information from multiple federal agencies and the White House through a device "very similar to a laptop" before sending the alert out, the official told CNN.

Prior to the nationwide test, officials from FEMA and the Federal Communications Commission conducted local tests and reported that 75 percent of phones successfully received the message. Those that did not may have been turned off or on a phone call. A mandatory test of the alert is required at least once every three years.