ST. PETERSBURG, Russia (AP) _ Russia on Saturday freed a retired naval officer accused of treason and espionage for helping a Norwegian environmental group.

Alexander Nikitin, 44, has been jailed since February for helping the environmental group Bellona with a report on radioactive contamination from Russia's Northern Fleet.

Amnesty International declared Nikitin a ``prisoner of conscience,'' its first in Russia since the Soviet breakup.

His lawyer, Yuri Shmidt, said the release followed a meeting Wednesday in Moscow with Russia's deputy prosecutor general, Mikhail Katyshev. According to Shmidt, the prosecutor appeared to agree that Nikitin was innocent of treason and promised to look into the case.

``I am completely convinced that the case will be closed and that there will be no trial,'' he said.

The ITAR-Tass news agency said Nikitin was freed on orders from Katyshev, on the condition that he not leave St. Petersburg.

Nikitin was resting at home late Saturday with his wife and teen-aged daughter, his lawyer said.

The charges against Nikitin were pressed by the Federal Security Service, the main successor to the Soviet KGB, which claims that material on nuclear submarine accidents in the Bellona report reveals state and military secrets.

Defense lawyers maintain most of the material was already a matter of public record. They also says Russian law forbids making any information about potential health and safety risks to the population classified.