'Trump alert': US mobile phone owners get test message

More than 200 million US mobile phones have received a "Presidential Alert" test.

The trial is designed to check that it has been used properly.

Unlike other alerts – such as natural disaster warnings – there was no way to opt out, except switching to a device or blocking its cellular connection.

Some have described the test as "Trump Alert" – but the US leader has been involved in the trial.

Instead, the nationwide event is being run by the Federal Emergency Management Agency (Fema), which would also be in direct control of the US President, Donald Trump.

It is intended to be used by major threats, including:

• missile attacks
• acts of terrorism
• natural disasters

The alert has been reported as saying: "This is a test of the National Wireless Emergency Alert System.

It was being broadcast from mobile phone for about 30 minutes from 14:18 ET (19:18 BST) – with devices displaying only a single message.

The test is mandated under a law that says it should be at least once every three years.

Hurricane Florence response efforts were continued in North and South Carolina.

Legal challenge

Congress has placed limits on the subject of such a warning, saying it must relate to a natural or man-made disaster or public safety threat.

Even so, there was a last-minute effort to block the use of the Presidential Alert system.

A journalist, a breastfeeding advocate and a fitness instructor teamed up to sue Fema, claiming the technology was a violation of their rights to be free from "government-compelled listening".

The legal action alleged that the test could be "traumatic" to the point of abuse.

"Officials – including [President] Trump – are free to define 'act of terrorism' and 'threat to public safety' as they read, possibly broadcasting arbitrated, biased, irrational and / or content-based messages to hundreds of millions of people, "the legal action claimed.

However, in New York, judge refused the request at a hearing on Wednesday morning.

Others have used social media to complain about mock the trial. Many have noticed that anyone wants to know the president's thoughts can turn to Twitter.

But in response, others have highlighted that the system has been developed and put in place during the presidencies of George W. Bush and Barack Obama.

Moreover, after two previous alert system errors – the first involving a false alarm about a missile attack on Hawaii, the second involving a presidential proclamation about Senator John McCain's death being sent to the wrong people – there is an argument that the technology needs to undergo regular public tests if it is to be relied on.