Norway has blamed Russia for a cyber attack on the email system in the Norwegian parliament in August.
Foreign Minister Ine Eriksen Soreide called it a serious incident affecting the country's "most important democratic institution," the BBC reports.
"Based on the information available to the government it is our assessment that Russia stood behind this activity" she said.
Moscow has rejected the claim, calling it a "serious and wilful provocation."
Soreide said Norway's security and intelligence services were "co-operating closely to deal with this matter at the national level."
In September, Norwegian authorities said that email accounts belonging to several officials had been compromised during a cyber attack, and some information had been downloaded.
The full extent of damage has not been revealed to the public.
In their annual risk assessment report in February, the Norwegian internal intelligence services warned against operations on the computer network which, according to them, constitute "a persistent and long-term threat to Norway," according to Euronews.
Russia's malign activity targeting Norway
In August, Norway expelled a Russian diplomat on espionage suspicions, while Russia made a mirror move.
Also in August, Norway's security police arrested a Norwegian citizen in Oslo on espionage charges. The individual, who has worked with the DNV GL AS classification firm, is being accused of handing to Russians sensitive information that could harm national interests.
In 2018, Norway arrested a Russian national who was suspected of gathering intelligence on the country's parliamentary network. The individual was later released due to a lack of evidence.
In a report earlier this year, Norway's military intelligence agency warned that Russia was trying to fuel discord in the country through so-called influence operations, aimed at weakening public trust in the government, election processes, and the media.