(Corrects a Dec. 19 story to make clear in graf 12 that Russia annexed Ukraine’s Crimea, not all of Ukraine)

MOSCOW/OSLO (Reuters) - Russia has detained a Norwegian citizen it suspects of spying, his Norwegian lawyer and the RIA news agency said on Tuesday, citing a Moscow court which sanctioned the individual’s detention.

Media reports said Russia’s FSB security service had caught the Norwegian taking secret documents about the Russian Navy from a Russian citizen.

The detained man is 62-year-old pensioner Frode Berg, a former guard working on the Norwegian-Russian border who was arrested on Dec. 5, his Norwegian lawyer told Reuters.

“His family says the accusations of espionage are inexplicable,” said Berg’s lawyer in Oslo, Brynjulf Risnes.

“He was on a private visit to meet acquaintances from his former job and the cultural work he does ... The family has known for a while that Frode Berg was arrested. They thought it was a misunderstanding and that it would be clarified soon.”

Berg resides in the Norwegian city of Kirkenes, a town some 15 kilometres (9 miles) from the border with Russia. He is active in a cross-border cultural organisation called Girls on the Bridge.

Berg posted a picture of a snow-covered Red Square on his Facebook profile page early on Dec. 5, the day of his arrest, with the message “Christmas Time in Moscow!”.

The maximum penalty for espionage in Russia is 20 years in prison, while the minimum sentence is 10 years, said Risnes.

“The family is struggling as there is very little information available from the Russian authorities,” he said.

He said his first priority was to get access to Berg and the second one was to ensure a Russian lawyer who could provide the best possible defence.

“Often espionage cases have political undertones,” he said. “So it is important we have a lawyer who fully defends his interests.”

NATO-member Norway is part of the coalition of countries that have imposed sanctions on Russia following its 2014 annexation of Ukraine’s Crimea. It has been concerned about Russia’s ability and willingness to use military means to achieve political goals.

Norwegian authorities said they had been able to visit their national in detention.

“The Norwegian consular service has visited the citizen that has been arrested in Moscow and is now in detention,” said Frode Overland Andersen, a press spokesman for the Norwegian Ministry of Foreign Affairs.

He added the Norwegian national had legal representation and that the arrest had taken place on Dec. 5. The spokesman declined to comment on the charges.