A Russian defence company worker has been jailed for eight years after being found guilty of passing missile secrets to foreign intelligence.
Alexander Gniteyev was also fined 100,000 roubles (£2,000) by a court in the city of Yekaterinburg.
The Russian Federal Security Service, the top KGB successor agency, said he had given missile secrets to foreign intelligence, but would not say which country he was spying for.
Deputy prime minister Dmitry Rogozin said on Twitter that Russia should toughen its punishment for espionage. “If they had sentenced him to 80 (years), that would have reduced the number of those eager to pass state secrets,” he tweeted.
Mr Rogozin said Gniteyev had handed over secrets related to the Bulava missile, developed to arm the latest generation of Russian nuclear submarines.
Military officials have repeatedly boasted of the Bulava’s ability to penetrate any prospective missile defences and described it as the core of the nation’s nuclear deterrent for years to come.
The Bulava suffered a string of failures during its development, but the latest launches have been fine and officials say it will be commissioned later this year.
The court verdict follows February’s conviction of a Russian military officer accused of providing the CIA with secret information on new missiles.
US-Russian relations have also soured over US-led Nato missile defence plans for Europe, which Russia sees as a potential threat to its nuclear forces.