Staff Sgt. Gordon Black, a U.S. soldier jailed in the Russian city of Vladivostok, has entered a guilty plea to theft charges and is cooperating with investigators in the case, Russia's state-run news outlets said Thursday.

"He is cooperating, he admitted [guilt]," the RIA news agency cited a representative of the local interior ministry as saying.

CBS News has been unable to obtain contact details for lawyers representing Black in Russia, and it was not possible to verify the information reported by Russian state media.

Black was detained in Vladivostok on May 2 and accused of stealing from a woman he was in a relationship with. A court has ordered him to remain in custody until at least July 2.

Black was stationed in Korea, Pentagon officials told CBS News, and was in the process of changing duty stations to Fort Cavazos, formerly known as Fort Hood, in the U.S. when he went to Russia on unofficial travel.

The soldier's mother, Melody Jones, said he was in Russia visiting his girlfriend.

"Please do not torture him [or] hurt him," Jones said when asked about her message to the Russians. 

National Security Council spokesman John Kirby told reporters earlier this month that the U.S. was "aware of this case," but that he said he couldn't "say much about it right now." 

The U.S. government has warned Americans repeatedly not to travel to Russia, citing "the potential for harassment and the singling out of U.S. citizens for detention by Russian government security officials" and other factors.

The Biden administration has been working to secure the release of two other Americans who it considers wrongfully detained in Russia. Paul Whelan, a former Marine, has been imprisoned since 2018 on espionage charges, which the U.S. and his family insist are totally baseless. He was sentenced to 16 years in prison in 2020.

Wall Street Journal reporter Evan Gershkovich was jailed in March 2023, also on espionage charges denied by his family, the newspaper and the U.S. government. He's still awaiting a trial.

The State Department said in December that Russia had rejected a "significant" proposal for the release of both men.

An updated travel advisory issued in September noted that the U.S. Embassy in Moscow had "limited ability to assist U.S. citizens in Russia."

Separately, a U.S. citizen identified by Russian authorities as Nikum William Russell was given a 10-day jail sentence for "petty hooliganism" after a court said he had stumbled drunkenly into a children's library in Moscow and passed out semi-naked.   

Camilla Schick and Arden Farhi contributed to this report.

In:
• Paul Whelan
• Evan Gershkovich
• Spying
• Russia
• Vladimir Putin
• U.S. Army

Tucker Reals

Tucker Reals is cbsnews.com's foreign editor, based in the CBS News London bureau. He has worked for CBS News since 2006, prior to which he worked for The Associated Press in Washington D.C. and London.