Vladivostok, Russia - The Russian secret service FSB has arrested a former employee of the US consulate in Vladivostok on espionage charges.

Robert Shonov, a Russian citizen, collected information on the course of the "special military operation" in Ukraine on behalf of the US embassy, the FSB said on Monday, using the Kremlin's term for the Russian invasion of its neighbor.

The man is also accused of having passed on information about mobilization processes and about the potential for protests ahead of the Russian presidential elections. He is said to have given this information to the embassy's political department in return for payment.

The FSB said two US diplomats would be interrogated in connection with the case.

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If convicted of collaborating with foreign powers to harm national security, the suspect faces up to eight years in prison.

The incident threatens to further strain the already tense relationship between Russia and the US amid the ongoing war.

Moscow has made similar arrests in the past, aiming to later exchange the detainees for Russian citizens held by the US.

Earlier this year, the Russian intelligence service arrested Wall Street Journal correspondent Evan Gershkovich on espionage charges.

Gershkovich and the newspaper deny the accusations. The journalist has been held in custody since the end of March and recently had his detention extended.