The pressure is building for Moscow to release a jailed Wall Street Journal reporter who has been formally charged with espionage in Russia and has entered his denial. On Friday, the Senate’s top two leaders demanded that Russia immediately release Evan Gershkovich. The rare bipartisan statement condemned the detention of the Journal reporter and declared that “journalism is not a crime.” 

The statement from the leader of the Senate Democrats, Charles Schumer, and the Senate minority leader, Mitch McConnell, comes as America is working to swiftly end what it calls the unlawful detention of Mr. Gershkovich, the first journalist to be held on alleged espionage since the Cold War.

“We strongly condemn the wrongful detention of U.S. citizen and Wall Street Journal reporter Evan Gershkovich, and demand the immediate release of this internationally known and respected independent journalist,” Messrs. Schumer and McConnell said.

They added that Mr. Gershkovich was accredited by the Russian Ministry of Foreign Affairs to work as a journalist in Russia and “Russian authorities have failed to present any credible evidence to justify their fabricated charges.” Messrs. Schumer and McConnell wrote: “Let there be no mistake: journalism is not a crime.”

American officials are working for the release of Mr. Gershkovich, 31, who was arrested late last month and is currently being held against his will in Moscow’s Lefortovo prison. The son of immigrants from the Soviet Union, he grew up speaking Russian at home at Princeton, New Jersey. Russia’s top security agency, the FSB, said Mr. Gershkovich was trying to obtain classified information about a Russian arms factory, but presented no evidence to support such a claim.

The Russian state news agency Tass reported Friday that Mr. Gershkovich had been charged with spying and officially entered his denial of the charge, which is widely seen as spurious and politically motivated. In the Russian legal system, the filing of charges means the formal start of a criminal probe. 

Tass quoted its source as saying: “The FSB investigation charged Gershkovich with espionage in the interests of his country. He categorically denied all accusations and stated that he was engaged in journalistic activities in Russia.”

The source declined further comment because the case was considered secret. 

President Biden told reporters last Friday that his message to Russia was: “Let him go.”

Secretary  Blinken said Wednesday he has “no doubt” that Russia has wrongfully detained Mr. Gershkovich. On Thursday, the American ambassador to Russia, Lynne T. Tracy, and Russia’s deputy foreign minister, Sergei Ryabkov, met to discuss the situation, but that initial conversation does not yet appear to have borne fruit. 

The Journal has adamantly denied the allegations against Mr. Gershkovich and demanded his release.

The Senate leaders said the American Embassy has been denied consular access “against standard diplomatic practice and likely in violation of international law.”

Messrs. Schumer and McConnell also said that Russia has a long history of unjustly detaining American citizens, and called for the release of another American, Paul Whelan.

Mr. Whelan, a Michigan corporate security executive, has been imprisoned in Russia since December 2018 on espionage charges that his family and Washington have said are baseless. He is serving a 16-year sentence.

An American professional basketball player, Brittney Griner, was imprisoned in Russia for nearly 10 months before being released in a prisoner exchange for a Russian arms dealer, Viktor Bout, late last year.