The United States and media freedom groups have voiced their disappointment with Russia's detention of a Wall Street Journal reporter, Evan Gershkovich, working out of their Moscow bureau on suspicion of spying.

The newspaper quickly said that the claim was not true, according to NPR.

Russian Federal Security Service (FSB) agents detained Gershkovich on Wednesday while on duty in the Ural Mountains city of Yekaterinburg.

Gershkovich had been collecting information on one of the military-industrial complex companies in Russia "acting on an assignment from the American side" that was classified as a state secret, according to FSB's statement. Several Russian military plants are in the Urals.

After a not-guilty plea to espionage charges, Gershkovich was officially arrested by a Moscow court and ordered to be held until May 29, awaiting an investigation, Russian media outlets reported.

The newspaper strongly refutes the FSB's accusations and demands Gershkovich's immediate freedom, according to the Wall Street Journal statement.

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White House Released a Statement on Evan Gershkovich Case

"We are deeply concerned by the troubling reports that Evan Gershkovich, an American citizen, has been detained in Russia," said Press Secretary Karine Jean-Pierre.

The White House and State Department officials spoke with the Wall Street Journal, where Mr. Gershkovich works, as well as his family. The State Department has also contacted the Russian government regarding this issue and has been working to gain Gershkovich's consular access, said the statement, adding that Russia's government's targeting of American residents is intolerable and they strongly disagree with Gershkovich's arrest.

They also stated their disapproval of the Russian government's ongoing assault on the press and the protection of press freedom.

"I want to strongly reiterate that Americans should heed the U.S. government's warning not to travel to Russia. U.S. citizens residing or traveling in Russia should depart immediately, as the State Department continues to advise," the statement concluded.

Family of Another Detained American in Russia Reacts on Evan Gershkovich Detainment

Negotiations between Washington and Moscow have been drawn out and challenging due to the detention of other Americans.

American basketball player Brittney Griner was freed from detention in December 2022 in exchange for Russian arms dealer Viktor Bout.

Griner was arrested in February 2022 on what the United States claimed were false drug smuggling charges.

The U.S., however, was unable to obtain the release of Paul Whelan, another American detained in Russia, according to CNN.

Whelan, a former Marine who holds citizenship in the United States, Ireland, the United Kingdom, and Canada, was arrested in a Moscow hotel in December 2018 on suspicion of participating in an intelligence operation, according to Russian officials.

He began serving his 16-year prison term in 2020, following a trial that U.S. authorities have deemed unfair.

"Our family is sorry to hear that another American family will have to experience the same trauma that we have had to endure for the past 1,553 days," Paul's brother David Whelan said in an email to the press on Thursday. "Unfortunately, the White House does not seem to have found a way to resolve cases like Paul's, where an American is falsely charged with espionage by the Kremlin."

The United States has maintained its efforts to have Paul Whelan released. The U.S. has reportedly made "serious proposals" to the Russian government, as stated by Secretary of State Antony Blinken earlier this month.

While David still hoped that Paul Whelan and Evan Gershkovich would soon be reunited with their families, he admitted that he had "started to wonder whether Paul's case is a priority" considering the release of other American citizens.

Despite the restrictions, the Wall Street Journal is one of the few Western publications to maintain coverage in Moscow, Russia.

READ MORE: Ex-U.S. Marine Trevor Reed Disappears in Russia Prison System 

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Written by: Bert Hoover

WATCH: Russia detains U.S. journalist Evan Gershkovich on espionage charges - From CBS News