By Terje Solsvik and Nerijus Adomaitis
OSLO (Reuters) - Norway is expelling 15 Russian embassy officials that the foreign ministry said on Thursday were intelligence officers operating under the cover of diplomatic positions, the latest such expulsion by a Western nation since Moscow invaded Ukraine.
The Russian embassy in Oslo told Reuters Norway's decision was "another extremely unfriendly step, which will see a response".
Some 40 Russian diplomats are currently accredited in Oslo, so the expulsions amount to more than a third of their number.
It is the latest instance of a Western country expelling Russian diplomats since Moscow launched its full-scale war against Ukraine last year. So far this year, Estonia, the Netherlands and Austria have also expelled Russian diplomats.
Norway also expelled three Russians in April 2022.
"Their activities pose a threat to Norway," Norwegian Foreign Minister Anniken Huitfeldt told a news conference.
"We have followed their activities over time. They have increased since the invasion of Ukraine."
The officers concerned must leave Norway shortly, she added.
The Russian foreign ministry said Moscow would respond to the expulsions, state-owned news agency TASS reported, without elaborating.
Norway, a member of the NATO military alliance, shares a border with Russia in the Arctic.
The expulsions could further complicate the process of transferring the chair of the Arctic Council, a multilateral body in which Arctic nations discuss issues affecting the polar region.
Moscow currently holds the chair but Norway is due to take over on May 11 and Oslo had said it would prioritise a smooth transition.
Huitfeldt said it was too early to say whether the expulsions would affect the Arctic Council transition.
The Nordic country still seeks to maintain normal diplomatic relations with Russia, and Russian diplomats are welcome in Norway, Huitfeldt said.