A Russian prosecutor says that a Norwegian man jailed on espionage charges has acquired classified information on Russian nuclear submarines.

Frode Berg was arrested in Moscow in December 2017. His lawyer says that Berg, a retired Norwegian border inspector, is the victim of a setup.

Prosecutor Milana Digayeva told Russian news agencies on Tuesday as Berg's trial began that the Norwegian man was collecting information about Russian nuclear submarines. The case is being heard behind closed doors for secrecy reasons.

Digayeva said that Berg, who was allegedly on the payroll of Norwegian intelligence, was caught red-handed with the documents he had received from an employee of a military facility who was shadowed by Russian intelligence.