MOSCOW (AP) — Wall Street Journal reporter Evan Gershkovich, arrested in Russia on espionage charges, lost an appeal on Thursday to be released from jail and will remain in custody at least until Jan. 30.

Gershkovich, 32, was detained in March while on a reporting trip to the Russian city of Yekaterinburg, about 2,000 kilometers (1,200 miles) east of Moscow. Russia’s Federal Security Service alleged that the reporter, “acting on the instructions of the American side, collected information constituting a state secret about the activities of one of the enterprises of the Russian military-industrial complex.” He has been behind bars ever since.

The Lefortovo District Court in Moscow on Nov. 28 ruled to extend his detention until the end of January, and the appeal Gershkovich has filed against that ruling was rejected by the Moscow City Court at a hearing Thursday.

Gershkovich and the Journal deny the allegations, and the U.S. government has declared him to be wrongfully detained. Russian authorities haven’t detailed any evidence to support the espionage charges.

Gershkovich is the first American reporter to be charged with espionage in Russia since 1986, when Nicholas Daniloff, a Moscow correspondent for U.S. News and World Report, was arrested by the KGB. He is being held at Moscow’s Lefortovo prison, notorious for its harsh conditions.

Analysts have pointed out that Moscow may be using jailed Americans as bargaining chips after U.S.-Russian tensions soared when Russia sent troops into Ukraine. At least two U.S. citizens arrested in Russia in recent years — including WNBA star Brittney Griner — have been exchanged for Russians jailed in the U.S.

The Russian Foreign Ministry has said it will consider a swap for Gershkovich only after a verdict in his trial. In Russia, espionage trials can last for more than a year.

The U.S. State Department said earlier this month that the Biden administration has made a new and significant offer aimed at securing the release of Gershkovich and another American detainee, Paul Whelan. Russia has rejected the offer, spokesman Matthew Miller said, without revealing either the details of the offer or why Russia had turned it down.

Lynne Tracy, the U.S. ambassador to Russia, attended the court hearing for Gershkovich's appeal on Thursday and told reporters that "Evan’s ordeal has now stretched on for over 250 days. His life has been put on hold for over eight months for a crime he didn’t commit.”

“Although Evan appeared as sharp and focused as ever today in the courtroom, it is not acceptable that Russian authorities have chosen to use him as a political pawn,” Tracy said after the hearing.