AT&T has gone down, leaving people unable to make phone calls – including to 911.

The outage at the US’s biggest phone network led to warnings from emergency services and advice from companies to get around the issue.

The problems began early on Thursday. AT&T said it was aware of the issue and working urgently to fix it – but did not give any indication of why it had happened or when it might be resolved.

AT&T has around 250 million customers, making it the US’s biggest phone network by some distance.

Follow for all the latest on the outage below.

Cybersecurity and Infrastructure Security Agency working with AT&T

18:00 , Michelle Del Rey

“CISA is aware of the reports and we are working closely with AT&T to understand the cause of the outage and its impacts, and stand ready to offer any assistance needed,” The agency’s Executive Assistant Director for Cybersecurity, Eric Goldstein, said in a statement.

Ron DeSantis address AT&T outage during news conference

17:45 , Michelle Del Rey

“Some of you may not have cell phone service this morning,” Mr DeSantis said while speaking to a crowd about the work of the Central Florida Tourism Oversight District on Thursday.

“You think about your daily life like...honestly it’s like imagine if we had an EMP attack or something like what would end up happening in this country,” he said. “It’s not necessarily a good thought.”

Virginia county urges residents to text 911 during outage

17:25 , Michelle Del Rey

Emergency officials are struggling to take in calls as the AT&T outage persists. In Virginia, officials with Prince William County, just an hour southwest from Washington DC, are asking their residents to text emergency services if they need to.

According to the Prince William Times, other officials in neighbouring counties are putting out the same notices, but are alerting residents to text 911 when possible.

AT&T says 75 per cent of network restored

17:04 , Michelle Del Rey

AT&T is saying that 75 per cent of its network has been restored.

“Our network teams took immediate action and so far three-quarters of our network has been restored,” the company said. “We are working as quickly as possible to restore service to remaining customers.”

AT&T refers customers to 'network update’ page

16:48 , Andrew Griffin

AT&T is now pointing affected customers to a special page on its website. It’s not very detailed:

“Some of our customers are experiencing wireless service interruptions this morning. Our network teams took immediate action and so far three-quarters of our network has been restored. We are working as quickly as possible to restore service to remaining customers.”

You can find the page here.

iPhones offer communication through satellites

16:31 , Andrew Griffin

Recent iPhones (the 14 and 15) include a new satellite connectivity feature that lets them connect to the world through satellites rather than traditional phone connections. It’s explained here.

You should be able to use that even if you are part of the AT&T outage. But note that it’s mostly intended for emergency situations – and that it comes with its own restrictions, such as requiring sight of the sky.

WiFi calling isn’t the only way to avoid the phone network

16:29 , Andrew Griffin

AT&T has recommended that affected users get onto WiFi and use that to call people. (Instructions are below.)

But there are plenty of other ways of communicating without a phone connection, too. You can

It’s also worth noting that there are plenty of ways to use services without an active internet connection, too. You can download maps offline, for instance (Google has long allowed this, and Apple Maps has recently introduced it, too). And you can download music and videos onto your phone ready for any long journeys.

Customers compare situation to Leave The World Behind

16:27 , Andrew Griffin

It’s only a few months since the release of Leave The World Behind, Netflix’s film with a tag line that does feel a little familiar today:

Of course, there is internet, and most phones are still working. But it is a reminder that such an outage is possible.

Marco Rubio uses outage to stoke fear about Chinese cyber attacks

16:25 , Andrew Griffin

Florida senator Marco Rubio has used the outage to stoke fear about a Chinese cyber attack. At the moment there is nothing to indicate whether the outage was intentional.

(Experts have warned about the danger of an attack of this kind on important infrastructure. But it’s not clear whether China actually intends to launch one.)

Was outage caused by a solar flare?

15:59 , Andrew Griffin

Probably not, says Ryan French, an astrophysicist.

Other networks appeared to be hit by AT&T outage

15:55 , Andrew Griffin

On tracking website Down Detector, as well as in complaints on Twitter, customers at rival networks such as Verizon and T-Mobile are also complaining about an outage.

But it appears that is just an effect of the AT&T outage, and is happening because people on that network are unable to call others. Both Verizon and T-Mobile have denied that they are having issues.

Customers ask for credit in response to outage

15:54 , Andrew Griffin

Many of AT&T’s customers are calling on the company to offer some credit in return for the outage. (The network has apologised, but not yet said anything about whether there will be any kind of compensation.)

Emergency services advise people to use other phones

15:50 , Andrew Griffin

This is a fairly representative message from emergency services across the US. They say they are aware of the problem and advise that people try different phones – and not to call 911 just to check whether it works.

Outage continues

15:49 , Andrew Griffin

Hours after it started, some AT&T customers still can’t get online. The company hasn’t said anything meaningful since it said that it had “identified” the problem – but it still doesn’t seem to be fixed.

How to use Wi-Fi calling

14:53 , Andrew Griffin

AT&T has advised affected customers to use WiFi calling. As the name suggests, that relies on WiFi and the internet to make calls, rather than the phone network. As such, it gets around the problems with the phone network (but does of course rely on you having access to a WiFi connection).

It’s turned on by opening up the Settings app on your iPhone or Android. Press “Cellular” on an iPhone or “Connection” on an Android, and then choose the WiFi calling option, which will allow you to turn it on and choose important settings.

You can find more information on AT&T’s website here.

AT&T says it has ‘located an outage'

14:50 , Andrew Griffin

In response to questions from customers, AT&T says it has “located” and “pinpointed an outage”.

“We don’t have an estimated time frame, but our team is on it,” it said on X/Twitter.

AT&T apologises to customers

14:49 , Andrew Griffin

AT&T has sent an array of different messages to affected customers today. But they are mostly along the lines of the below:

“We sincerely apologize for the inconvenience that is happening and some of our customers are experiencing wireless service interruptions this morning. We are working urgently to restore service to them. We encourage the use of Wi-Fi calling until service is restored.”

Hello and welcome...

14:46 , Andrew Griffin

... to The Independent’s live coverage of the outage at AT&T.