A Russian court on Tuesday extended the arrest of Wall Street Journal reporter Evan Gershkovich by three months in a closed-door hearing emblematic of the secrecy that has marked the case against the first U.S. correspondent since the Cold War to be detained in Russia on spying charges.

Gershkovich, a 31-year-old American citizen, was ordered held until Aug. 30. He had been arrested in March on espionage charges on a reporting trip in Russia. He, his employer and the U.S. government have denied the charges.

Tuesday’s pre-trial hearing wasn’t announced in advance, and the entire case has been wrapped in secrecy.

Russian authorities haven’t detailed what — if any — evidence they have gathered to support the espionage charges.

Various legal proceedings have been closed to the media. No details immediately emerged about whether Gershkovich attended Tuesday’s hearing or what was said. Tass said the session was closed because the reporter was accused of possession of “secret materials.”

One Russian news agency, Interfax, quoted a court official as saying Gershkovich’s parents — themselves Soviet emigres living in New Jersey — were visiting Moscow and had been admitted to the court building but not into Tuesday’s hearing. The U.S. State Department said at least one U.S. Embassy official attended the hearing.

Gershkovich’s arrest has rattled journalists in the country and drawn outrage in the West.

The U.S. government has declared Gershkovich to be “wrongfully detained” and demanded his immediate release. He’s being held in Moscow’s Lefortovo prison.

U.S. Embassy officials were allowed at least one prison visit to Gershkovich since his arrest in Yekaterinburg on March 29, but Russian authorities have denied permission for other visits.

State Department spokesman Matthew Miller told reporters in Washington, “We once again call on Russia to comply with their obligation to provide consular access to him.” He added that the charges against Gershkovich “are baseless and we continue to call for his immediate release as well as for the immediate release of Paul Whelan.”

Whelan, a Michigan corporate security executive, is serving a 16-year espionage sentence in a remote Russian prison. The retired U.S. Marine was detained in 2018. Whelan and Washington deny he spied in Russia.

The Biden administration had hoped to secure Whelan’s release during negotiations on a prisoner exchange that eventually freed American basketball star Brittney Griner from a Russian prison last December.

Analysts have pointed out that Moscow may be using jailed Americans as bargaining chips in soaring U.S.-Russian tensions over the Kremlin’s military operation in Ukraine.

In a statement after Tuesday’s hearing, the Wall Street Journal said: “While we expected there would be no change to Evan’s wrongful detention, we are deeply disappointed. The accusations are demonstrably false, and we continue to demand his immediate release.”