OSLO: Norway's second-largest media group and one of Europe's largest on Wednesday (Thursday in Manila) said a ransomware attack has halted the publication of some of its local newspapers in print for the foreseeable future.

Amedia said digital intruders were demanding a ransom to hand back control of affected servers after the cyberattack targeted the company in the night of Monday to Tuesday.

The group's IT director Pal Nedregotten warned of the "painstaking work" needed to restore the servers, a process he predicted will take "quite a long time."

"It is a classic ransomware virus attack, where the intruder has invaded parts of our servers, encrypted our data and left a business card," he told Norway's public broadcaster NRK.

Nedregotten added that the company was "not going to enter into a dialogue" about the ransom.

The attack has prevented Amedia from publishing the print editions of its local newspapers but has not affected the online versions.

The company said it should be able to print around 20 of its 100 newspapers on Thursday as it works to rescue its stricken servers.

Amedia also owns printers — though no newspaper — in Russia but noticed no disruption to its business there.