Hundreds of millions of Americans have received a presidential alert test on their phones from Donald Trump.

On Wednesday afternoon, an estimated 225 million people were sent the notification - accompanied by a loud tone and a vibration.

It read: "Presidential Alert. THIS IS A TEST of the National Wireless Emergency Alert System. No action is needed."

Two minutes later, people watching television and listening to the radio also received an alert.

The Federal Emergency Management Agency (FEMA) was testing the system to alert people about national emergencies for the first time.


But with people unable to opt out, the hashtag #PresidentialAlert became the top trending topic in the US on Twitter as people complained and joked about it.

Hours before the message was sent, a federal judge in New York rejected a lawsuit which sought to stop the messages.

NOOOOOOO THE ALERT. IT HAPPENED — christine teigen (@chrissyteigen) October 3, 2018

The lawsuit against Mr Trump and FEMA administrator Brock Long said the system was a "violation of Americans' first and fourth Amendment rights to be free from government-compelled listening, as well as warrantless, non-consensual trespass into and seizure of their cellular devices".

People on Twitter agreed, with actor and activist George Takei tweeting: "Oh my. A 'Presidential Alert' emergency. I thought that was the entire Trump presidency."

Singer Katy Perry posted a screen shot with the caption: "BLOCKS."

My mom asked me how to turn off her phone cause she said she didn’t want trump texting her. — B-Rye McDezzz (@B_RY3) October 3, 2018

Model and chef Chrissy Teigan said: "NOOOOOOO THE ALERT. IT HAPPENED."

Actress Frances Fisher tweeted: "How do I stop a sexual predator from texting me? Asking for 225,000,000 friends."

One woman said: "My mom asked me how to turn off her phone cause she said she didn't want Trump texting her."

Others altered the words of the message, including the Brooklyn Nets basketball team who tweeted: "THIS IS A TEST OF THE BKN WIRELESS ALERT SYSTEM.

"THE NETS ARE PLAYING TONIGHT."

Stephen Colbert from The Late Show tweeted a picture of an altered message in a Trump-style Tweet, saying: "TRUMP NATIONAL ALERT. Huge wave! Very wet in terms of water. I'll be there with paper towels soon."

He added: "If there's a tsunami, Trump is the last person I want a text from."

Miami Zoo used the opportunity to post a video of a baby hippo having a bath.

⚠️ EMERGENCY ALERT! ⚠️

Our adorable baby Pygmy Hippo is taking a bath and it is WAY TOO CUTE!

No further action is needed. #PresidentialAlert #ZooMiami pic.twitter.com/CU7UIAVh89 — Zoo Miami (@zoomiami) October 4, 2018

The Wireless Emergency Alert (WEA) system was launched in 2012 following criticism of George W Bush's handling of Hurricane Katrina in 2005, but Wednesday marked its first-ever nationwide test.

It was meant to be tested on 20 September, but this was postponed because of Hurricane Florence.

"When those messages appear on mobile devices, people should take those extremely seriously," Antwane Johnson, director of the IPAWS system, told CBS News.

"It has some direct impact on either life or safety."