Russia on Thursday announced that it has launched a criminal case against an unnamed American suspected of espionage. 

In a statement, Russia's Federal Security Service said the individual "is suspected of collecting intelligence information on biological topics directed against the security of the Russian Federation." 

"The Federal Security Service of the Russian Federation initiated a criminal case against a US citizen on the grounds of a crime under Article 276 of the Criminal Code of the Russian Federation ‘Espionage,’" it added. 

Information about the nature of the allegations was not immediately available. 

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Russia FSB headquarters Moscow

Russia’s Federal Security Service (FSB), whose headquarters are shown here in Moscow, announced the investigation of an unnamed American suspected of "espionage." (Hohlfeld/ullstein bild via Getty Images)

It also is unclear if the American is currently being detained. 

A State Department spokesman told Fox News Thursday that it is "aware of unconfirmed reports of an investigation regarding a U.S. citizen in Russia," adding "we are looking into the matter and will continue to monitor the situation closely."

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Bout and Griner in photos

This combo of images shows Viktor Bout, left, a suspected Russian arms dealer at the criminal court in Bangkok, on Aug. 20, 2010 and WNBA star and two-time Olympic gold medalist Brittney Griner, right, in a courtroom prior to a hearing, in Khimki, outside of Moscow, Russia, on July 27, 2022. (AP Photo/Apichart Weerawong, left, and Alexander Zemlianichenko, File)

News of the investigation comes exactly six weeks after WBNA player Brittney Griner was freed from Russia in a prisoner swap for convicted Russian arms dealer Viktor Bout. 

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Paul Whelan, another American imprisoned in Russia, was not a part of that swap in December. 

Paul Whelan in 2020

Paul Whelan, a former U.S. marine who was arrested for alleged spying, is pictured in a courtroom in Moscow, Russia, on June 15, 2020.  (Sofia Sandurskaya, Moscow News Agency photo via AP, File)

He has been jailed on espionage charges that his family and the U.S. government have said are baseless. 

Fox News’ Ryan Gaydos and Nick Kalman contributed to this report.