(LONDON) — A Wall Street Journal reporter detained in Russia on espionage charges had his appeal denied in court on Thursday.

Evan Gershkovich, a correspondent with the paper’s Moscow bureau, was arrested in March and stands accused of “acting on the instructions of the American side” and collecting state secrets about the military.

The reporter arrived in Moscow City court on Thursday wearing a black T-shirt and jeans. He was placed in a glass enclosure within the courtroom, which is common for defendants in Russia’s legal system.

The United States was “extremely disappointed” in the decision, Lynne Tracy, the U.S. ambassador to Russia, said at the court. She reiterated the U.S. position that charges against Gershkovich are “baseless” and called for his release.

“Nevertheless today in the court room Evan continued to show remarkable strength and resilience in the face of these very difficult circumstances,” she said.

A judge in April denied another appeal, extending Gershkovich’s detention. In a hearing in Moscow’s Lefortovo Court in May, a judge further extended his pre-trial detention until August 30.

The case against Gershkovich amounts to a “sham,” Vedant Patel, a State Department spokesperson, said during a press briefing on Wednesday.

“We’ve been very clear that Evan is wrongfully detained — being wrongfully detained and targeted for simply doing his job as a journalist,” Patel said.

Tracy also attended the reporter’s appeal hearing in April. Speaking outside the court following the denial, Tracy said the charges were “baseless” and called again for Russian authorities to release Gershkovich.

Gershkovich’s parents, Mikhail Gershkovich and Ella Milman, traveled to Moscow for their son’s May hearing, the Journal reported.

“Any parent who loves their kid would travel to the end of the world to be with them for five minutes,” Milman told the Journal after the hearing.

President Joe Biden, who spoke with Gershkovich’s family in April, said the detention was “totally illegal.”

State department officials said the U.S. determined the journalist had been “wrongfully detained.” The House of Representatives earlier this month unanimously passed a resolution calling for the immediate release of Gershkovich and Paul Whelan, another American being held in Russia.

Emma Tucker, Editor in Chief of The Wall Street Journal, and Almar Latour, CEO of Dow Jones and Publisher of The Wall Street Journal, issued a statement on June 13 applauding the support from lawmakers.

“His wrongful detention is a blow to press freedom, and it should matter to anyone who values free society,” their statement said. “We will not rest until he is free.”

ABC News’ Guy Davies, Patrick Reevell, Shannon Crawford and Joe Simonetti contributed to this story.

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