Robert Shonov, a Russian national, is accused of “co-operating on a confidential basis with a foreign state” by Moscow's FSB spy agency – charges rejected by the US.
The FSB described him as an “informer of the US embassy” who “collected data on the special military operation”, the Kremlin's euphemism for the invasion of Ukraine.
Mr Shonov is suspected of gathering information on “mobilisation processes across Russia, related problems and their impact on protest moods among the population ahead of the 2024 Russian presidential election”.
He could face three to eight years in prison and a fine of $10,400. The FSB also wants to question two employees of the US embassy in Moscow, according to a statement published by Russian news agency Tass.
Mr Shonov was detained in May. The US State Department said the allegations were “wholly without merit”.
It said Mr Shonov, who had worked for the consulate in Russia's far east for 25 years, was merely responsible for compiling publicly available media reports. The mission in Vladivostok has been closed since 2020.
Russia last year lengthened prison terms for “confidential co-operation”. The US has called the law's invocation a “blatant use of increasingly repressive laws against its own citizens”.
Detained Wall Street Journal reporter Evan Gershkovich, who also faces Russian espionage charges, is appealing a decision to keep him in pretrial custody until November.
Gershkovich, the first US journalist since the Cold War to be held on espionage claims in Russia, had his detention extended in a closed-door court hearing last Thursday.
The FSB accuses him of collecting state secrets on Russia's military-industrial complex. The US says the charges are baseless.