COPENHAGEN, DENMARK -- The Russian Embassy in Norway's capital denied knowing anything about a man suspected of spying in the northern European country and alleged Wednesday that authorities there have used drone and ship sightings, as well as Russians with cameras, to fuel "spy mania."

A 37-year-old Brazilian citizen who worked at a university in the Arctic city of Tromsoe was detained Monday. The Norwegian Police Security Service alleged the man used a false name and identity while actually working for one of Russia's intelligence services.

The Russian Embassy said it "does not know who and what this is about."

"Everything Russian, whether public agencies, private companies or individuals, is suspicious and has a smell of espionage," the diplomatic mission said in an email. "The fact that different issues come up as if on a conveyor belt is no doubt no accident. All this is politically motivated."

The Norwegian security service identified the detained man as a "Brazilian researcher" at the Arctic University of Norway in Tromsoe. A university administrator described him as a guest lecturer. A court on Tuesday ordered him detained for four weeks.

In recent weeks, authorities in NATO member Norway, a major oil and gas producer, have reported several drone sightings near offshore installations in the North Sea. Several Russian citizens also were briefly detained for either flying drones or allegedly taking photos of objects covered by a photography ban.

The Norwegian government also has monitored Russian research ships and restricted Russian fishing vessels to three Arctic ports, where all Russian boats are subject to checks. Norway's Arctic border with Russia is 198 kilometres (123 miles) long.

"Recently, spy mania has been actively promoted in Norway," the Russian Embassy said.

Many 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.

The suspected sabotage of the Nord Stream 1 and 2 pipelines in the Baltic Sea happened a day before Norway opened a new Baltic pipeline to Poland.