Millions of Australians have been left without mobile and internet after a network failure at telecommunications giant Optus.
Optus is the country’s second-largest provider, with more than 10 million individual customers and hundreds of thousands more businesses.
The outage has caused transport delays, cut hospital phone lines, and downed payment systems.
Its cause is unclear, but Optus says there is no evidence of a cyber attack.
The company made last year suffered what was believed to be the biggest data breach in Australian history, as a result of a cyber attack.
The disruption left people across the country unable to call emergency services and critical helpline numbers, while also temporarily crippling train services in the state of Victoria and some hospital communications.
Wednesday’s disruption was reported around 04:00 (17:00 GMT). In an update seven hours later, CEO Kelly Bayer Rosmarin said her team had not yet identified what went wrong.
“The teams are trying many different angles and we will not rest until the service is back up for our customers,” she said, calling in to local radio via WhatsApp.
The firm later said that it had started restoring some of its services.
The disruption was also affecting other providers which use the Optus network, including Amaysim, Aussie Broadband, Moose Mobile, and more.
One Optus customer told the Australian Broadcasting Corporation the incident has left her unable to receive important updates about her father’s cancer treatment.
“I’m just waiting for results, and I can’t even get those through,” Danielle Hopwood said.
Another customer, Annie, told local radio she found out about the disruption when her cat’s automatic Wi-Fi-enabled feeder failed.
Australia’s Communications Minister, Michelle Rowland, said it has been an anxious morning for many Australians and called for the company to be transparent and “timely” in their updates to customers.
“My understanding is that this is a fault deep in the core… so it is a fault that is quite fundamental to the network,” she said.
Ms Bayer Rosmarin has apologised for the disruption and said the company will provide updates throughout the day.