A raft of global institutions – including major banks, media outlets and airlines – have reported being hit by a mass IT outage.

Australia has been particularly hard hit with flights grounded, supermarkets experiencing checkout chaos, and broadcast networks left scrambling on air as autocue, graphics and computers failed.

The US state of Alaska has also warned its emergency services are affected.

The cause of the outage is unclear, but many of those affected have linked it to Microsoft PC operating systems.

An official Microsoft 365 service update posted to X earlier in the day said ” we’re investigating an issue impacting users ability to access various Microsoft 365 apps and services”.

However, a Microsoft spokesperson told the BBC on Friday that “the majority of services were recovered” hours earlier.

A spokesperson for Australia’s Home Affairs Minister said the outage appears to be related to an issue at global cybersecurity firm Crowdstrike, and the country’s cybersecurity watchdog said there is no information to suggest it an attack.

“Our current information is this outage relates to a technical issue with a third-party software platform employed by affected companies,” they said in a statement.

Alaskan officials said many 911 and non-emergency call centres are not working properly.

Australian telecom firm Telstra has said triple-0 call centres – the main emergency contact in Australia – are not affected, but that it is working with other state emergency services providers to implement backup processes.

Meanwhile at Sydney Airport, information disappeared from departure boards. In an announcement to passengers in the domestic terminal, budget carrier Jetstar said that an “issue with Microsoft” meant it was unable to check in passengers, or to board its flights.

Virgin Australia also told its travellers there was a “complete ground stop” of flights.

Social media users have reported queues at Australian stores like Woolworths, with payment systems downed, and trouble accessing financial institutions like the National Australia Bank.