"I have requested a sentence of 14 years in jail. The ruling will be announced on April 16," the prosecutor said.
Berg denies the accusations.
The Russian authorities believe he served as a courier to bring documents and cash for Norway's military intelligence unit known as E-tjenesten.
According to his attorneys, Berg, who is facing a minimum of six years in prison but can be sentenced to as long as 20 years, denies being a spy.