A handful of Norwegian government services have been disrupted for more than a day after a large-scale cyberattack targeted the infrastructure used to operate them, authorities said.

The Norwegian Digitalisation Agency, known as Digdir, said the distributed denial-of-service (DDoS) attack began Monday and targeted the infrastructure of its IT partner, Vivicta. Such attacks flood servers with traffic in an attempt to make them unavailable to legitimate users.

Digdir said it was working with Vivicta to stabilize the affected systems, with some services gradually coming back online. The attack has continued for around 30 hours at varying levels of intensity and, as of Tuesday morning, was still affecting some services, according to Digdir's status page.

The incident disrupted 10 digital services used for verifying people's identities, logging into public services, exchanging data and documents between government agencies and businesses, accessing public records, and managing employee access.