OSLO/MOSCOW (Reuters) - Russia’s foreign ministry summoned Norway’s ambassador on Monday to protest against the arrest of a Russian citizen in Oslo on suspicion of spying while Norwegian authorities sealed off what was described as a “compromised room” in parliament.

FILE PHOTO: Norway's parliament seen in Oslo, May 31, 2017. REUTERS/Ints Kalnins/File Photo

The Russian, identified as M.A.Bochkaryov, was detained on Friday at Oslo’s airport as he prepared to fly out after attending an international seminar on digitalisation in Norway’s parliament.

“We demanded ... the immediate lifting of the absurd charges, and his release,” the Russian foreign ministry said, announcing its protest via Norway’s ambassador .

Bochkaryov, who was said by the foreign ministry to be a “staff member” of the Russian parliament’s upper house, had been attending a seminar in the Norwegian parliament. Organised by the European Centre for Parliamentary Research and Documentation, it had been attended by 79 people from 34 countries.

Norway’s Police Security Service (PST) said the Russian had been detained on suspicion of illegal intelligence activities.

Meanwhile, in preventive measures, the Norwegian authorities took out of service several printers in the public areas near the seminar’s venue.

The foreign affairs and defence committee’s meeting room in the building, one floor below the venue, was sealed until further notice. “The room has been compromised and cannot be used,” Conservative parliamentarian Michael Tetzschner said.

“We take this incident very seriously and therefore we have implemented preventive security measures in cooperation with the relevant authorities including the National Security Agency,” the parliament’s chief administrator, Marianne Andreassen, said.

The latest escalation in Russian-Norwegian relations comes as NATO prepares for the largest exercise on its northern flank since the Cold War.

Norway is a member of the U.S.-led NATO alliance and has a land border with Russia.

A “MISUNDERSTANDING”

“I cannot remember that we had a similar situation before, so it’s not normal,” said Martin Bernsen, spokesman for the Norwegian Police Security Service.

Hege Aakre, a Norwegian lawyer for the detained Russian, told Reuters his detention had been based on observation of his “suspicious behaviour”.

Her client had denied any wrongdoing and regarded the incident as “misunderstanding”, Aakre said. He appealed against the detention on Monday, she added.

The Russian consul visited the detained man and spoke with him, Russia’s TASS news agency reported on Monday, citing an Russian embassy official Olga Kiryak.

Last December, Russia arrested a retired Norwegian border guard Frode Berg in Moscow on suspicion of espionage.

Berg had admitted being a courier for Norway’s military intelligence but had scant knowledge of the operation he took part in and denied wrongdoing, his lawyer said.

The lawyer, Brynjulf Risnes, said the detention of the Russian man in Oslo offered the hope of a prisoner swap. “It sparks a hope for Berg and his family,” he told Reuters.

Berg faces up to 20 years of imprisonment if found guilty.