The US Justice Department unveiled spying charges Friday against a Russian who, under a Brazilian alias, studied at a Washington university and then tried to join the International Criminal Court in The Hague.

The Justice Department's indictment of Sergey Vladimirovich Cherkasov suggests it will try to contest his extradition to Russia from Brazil, where he is currently jailed on identity fraud charges.

Cherkasov, 39, was detained at the beginning of April 2022 by Dutch authorities for using fake identity papers.

He arrived in the country as Viktor Muller Ferreira, a Brazilian, to take a position at the ICC as a junior analyst.

But Netherlands police determined that he was not Brazilian, but rather an agent of Moscow's GRU military intelligence.

He was what is called an "illegal," a spy who lives abroad for years under deep cover, developing an entirely new identity.

That included spending 2018-2020 in a masters degree program at Johns Hopkins University's international studies program in Washington, according to the US indictment and a CV he posted online.

The Dutch said that if Cherkasov had worked at the ICC, he could have accessed "highly valuable" intelligence on its probe into war crimes in Ukraine or even influenced criminal proceedings at the Hague-based tribunal.

He was deported on April 3 to Brazil, where he was charged with identity fraud.

Chersakov was sentenced in July to 15 years in jail.

But by September, Moscow formally requested Brasilia deport him to Russia, where he was allegedly wanted for drug trafficking.

The US Justice Department charged him for illegally acting as an agent of a foreign power while he was in the United States.

They said that while a student in Washington, he collected information on unidentified Americans which he passed to his handlers, the department said.

He was also charged with visa fraud, bank fraud, wire fraud, and other counts stemming from his activities in the United States.

It was not immediately clear if or when the US Justice Department would seek his extradition from Brazil.

"When foreign adversaries, such as Russia, send undercover operatives into the United States, we will find them and prosecute them to the fullest extent of the law,” said US Attorney Matthew Graves.