Oslo’s domestic security agency detained the man and a local court ordered him to be held for four weeks.
Martin Bernsen, a spokesman for the Norwegian Police Security Service (PST) confirmed a suspected spy had been detained and said the case was “huge” but did not give further details.
In a statement, Arctic University of Norway administrator Jorgen Fossland said the person in question was “a guest lecturer” at the school. Mr Fossland referred other questions to the security service.
The man was detained on Monday in the Arctic city of Tromso, where the university is located. PST deputy chief Hedvig Moe said the man is “a Brazilian citizen, but we believe he, in reality, is Russian”.
The detained man’s lawyer, Thomas Hansen, told Norwegian newspaper VG his client denies any wrongdoing.
Investigators think he was in the Nato member country under a false name and identity while working for one of Russia’s intelligence services, Ms Moe said. He will be expelled from the Scandinavian country “because we believe he represents a threat to fundamental national interests”.
The security service “is concerned that he may have acquired information about Norway‘s policy in the northern region,” Ms Moe said.
“He has a network and the information which bit-by-bit are not a threat to the security of the kingdom, but we are worried that the information could be misused by Russia. We do not want this to fall into the hands of the Russians,” she said.
The university lecturer was apprehended Monday. He had been in Norway since 202 and has researched the northern regions and hybrid threats, Norwegian media said. Norway‘s Arctic border with Russia is 198 kilometres (123 miles) long.
He is the latest of several Russian citizens to have been detained in Norway in recent weeks. They include three men and a woman who were seen allegedly taking photographs of objects covered by a photography ban. They have since been released.
European nations have heightened security around key energy, internet and power infrastructure following underwater explosions that ruptured two natural gas pipelines in the Baltic Sea that were built to deliver Russian gas to Germany.
The damaged Nord Stream pipelines off Sweden and Denmark discharged huge amounts of methane, a potent greenhouse gas, into the air.
Ms Moe said the detention in Tromso was unrelated to the suspected sabotage of the pipelines.
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