A United States journalist working for the Wall Street Journal, Evan Gershkovich, has been arrested in Russia and accused of spying.

Gershkovich was working in Yekaterinburg at the time of his detention.

The Wall Street Journal said it was “deeply concerned” for his safety and vehemently denied the allegations against him.

The Kremlin claimed the reporter had been “caught red-handed”.

The FSB said it had “halted illegal activities”, adding that the reporter had been “acting on US instructions” and “collecting state secrets”.

Hours later, the security service took him to Lefortovo district court in Moscow for his formal arrest.

He was later seen being escorted from the building before being driven away. The court ordered his detention until 29 May, Interfax news agency reports.

His lawyer said he had not been allowed into the courtroom and Tass news agency reported the journalist had denied the charge.

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The court had earlier been cleared of staff and visitors because of a bomb threat.

The FSB confirmed in its statement that Gershkovich had foreign ministry accreditation while working in Yekaterinburg 1,800km (1,100 miles) east of Moscow.

His last WSJ piece this week reported on Russia’s declining economy and how the Kremlin was having to deal with “ballooning military expenditures” while maintaining social spending.

But the FSB claimed he had been detained “acting on US instructions” and that he had “collected information constituting a state secret about the activities of a Russian defence enterprise”.

A criminal espionage case was launched by the FSB’s investigation department, it added.

In a statement, the Wall Street Journal said it stood in solidarity with the reporter and his family: “The Wall Street Journal vehemently denies the allegations from the FSB and seeks the immediate release of our trusted and dedicated reporter, Evan Gershkovich.”

Tensions between the Kremlin and the West have become increasingly tense in the 13 months of Russia’s war in Ukraine. Press freedom watchdog Reporters Without Borders said it was “alarmed by what looks like retaliation”.

Russian Deputy Foreign Minister, Sergei Ryabkov, told local news agencies that it was too early to discuss prisoner swaps, saying: “I would not even put the question in this plane now, because you understand that some exchanges that happened in the past took place for people who were already serving sentences.”

Several US citizens are being held in Russia. Days before the invasion, American basketball star Brittney Griner was detained at a Moscow airport and jailed for carrying cannabis oil.

It was 10 months before she was freed in exchange for notorious Russian arms dealer Viktor Bout.

The Star