Millions of cellphones across the nation Wednesday afternoon received a “presidential alert.”

The alert read: “This is a test of the National Wireless Emergency Alert System. No action needed. “

It was sent out by FEMA starting at 2:18 p.m.

Officials say the system would be used to inform the public about dangerous weather, missing children or terror threats.

A lawsuit was filed in New York to stop the alert system, claiming it's a "violation of the First and Fourth Amendment rights to be free from government-compelled listening."

Unlike Amber Alerts or alerts from the National Weather Service, Americans will not be able to opt out of receiving presidential alerts.