Telephone and internet services have been restored to Shetland after two undersea cables were damaged, leaving the islands almost cut off from the outside world.

Police Scotland declared a major incident on Thursday after the cable linking Shetland to mainland Scotland was hit early that morning, leaving many islanders without mobile services, internet and in some cases landlines.

Engineers were already waiting to repair another undersea cable to the mainland, via the Faroe Islands, which was damaged last week. It was feared that connections would be restored before Saturday.

BT Group said its engineers had restored services with a temporary fix, but were continuing to work “hard” to fully repair the breaks, blamed by British and Faroese officials on fishing vessels trawling or dredging for the taken.

“While both cable links are being repaired by underwater engineers, engineers were able to reconnect all services through a temporary fix on Thursday afternoon,” a spokesperson said.

“Additional testing and monitoring overnight has shown that broadband services have remained stable, and we will continue to monitor this. As a precaution, we have specialist teams in Shetland with backup satellite links in case one of the submarine cables fails during their repair.

Faeroese Telecom infrastructure manager Páll Vesturbu said the damage to the continental link had affected the fibers in the cable, but “they weren’t cut”.

“We have reason to believe the cable was damaged by a fishing boat,” he told the BBC. “There was also an incident last week, and we also believe it was caused by a fishing boat.”

On Thursday, police had set up high-visibility patrols across the islands and urged residents to watch vulnerable or elderly neighbors and relatives in case they needed help.

The outage left the Shetland Islands council without landline services. The vending machines have stopped working. Planes continued to operate from Sumburgh Airport on Thursday, but all network and mobile links from the airport had failed.