The Kremlin has claimed that detained Wall Street Journal reporter Evan Gershkovich “violated Russian law” after the US said he was “wrongfully detained” and called for his release.
Mr Gershkovich, who covered Russia for the newspaper, was arrested last month while on assignment in the city of Yekaterinburg.
Russian officials have charged him with spying, which is rejected by the US government, the Wall Street Journal and human rights groups. It is the first time Russia has accused a US journalist of espionage since the Cold War.
On Tuesday, the Kremlin claimed the reporter had been caught “red-handed” on espionage charges - but has offered no evidence to support its claim.
Russia's FSB security service said last month it had arrested Mr Gershkovich, accusing him of gathering information about a Russian defence company that was a state secret.
The latest comments came after the United States had earlier this week designated Mr Gershkovich as wrongfully detained, effectively calling the charges bogus.
The US government transferred the case from the State Department to the office of the Special Envoy for Hostage Affairs, raising the political profile of Mr Gershkovich’s attention.
Asked about it on Tuesday, Kremlin spokesman Dmitry Peskov insisted the journalist had broken the law.
“I don't understand what kind of innovations this new regime is introducing. As for what it means, I don't know," Peskov said of the US designation.
He said Gershkovich had “been caught red-handed and violated the laws of the Russian Federation", before adding: “This is what he's suspected of, but of course, the court will make a decision".
More than 99% of criminal cases in Russia end in a conviction for the prosecution and the country has long been criticised by human rights bodies for a lack of fair trials.
Russia has presented no evidence to support the case against Mr Gershkovich, which is proceeding in secret because Russia says the case materials are confidential.
Next week, a court will hear an appeal from the journalist’s legal team against an order that he be held in pre-trial detention at Moscow's Lefortovo prison until May 29.
In designating the arrest as wrongful, the US government called for Putin’s regime to release him.
“Journalism is not a crime,” said the US State Department.
“We condemn the Kremlin’s continued repression of independent voices in Russia, and its ongoing war against the truth.”
The White House has previously called the espionage charge, which carries a jail term of up to 20 years, “ridiculous."
US officials have also called on Russia to release Paul Whelan, a former US Marine serving a 16-year sentence in a Russian prison, who is also designated by Washington as “wrongfully detained."
Factors which can decide whether someone is “wrongfully detained” include whether the individual is being targeted primarily because they are an American citizen or whether the detention is intended to influence US government policy.
