A Moscow Ñourt ruled on Thursday that Wall Street Journal reporter Evan Gershkovich must remain in custody.
Gershkovich was arrested on March 29 in the Urals city of Yekaterinburg on charges of espionage that carry up to 20 years in prison.
The reporter, who denies the charges, will remain in custody until at least January, 30, next month.
He is the first US journalist to be detained on spy charges in Russia since the Cold War.
Russia said Gershkovich was caught "red-handed" while the FSB, the main successor to the Soviet-era KGB, said he was trying to obtain military secrets.
The Wall Street Journal and Dow Jones say that Gershkovich was simply doing his job in Russia and deny the espionage charges. The Journal and Dow have repeatedly demanded that Russia release him, to no avail.
"Evan has now been unjustly imprisoned for nearly 250 days, and every day is a day too long," The Journal said in a statement.
"The accusations against him are categorically false and his continued imprisonment is a brazen and outrageous attack on a free press, which is critical for a free society. We continue to stand with Evan and call for his immediate release."
"We are deeply concerned by the court’s decision," the U.S. embassy in Moscow said. "We reiterate our call for his immediate release."
Diplomats say that Gershkovich was probably detained as part of broader Russian effort to build up a store of arrested US citizens who could we swapped for Russian citizens - and convicted spies - detained in the West.
Russian officials, who insist Gershkovich was caught seeking secrets, say there have been contacts with Washington over Gershkovich but they say that loud American public demands will not help his case.
Russia has said there could be no exchange involving Gershkovich until a verdict is reached in his case. No date has so far been announced for his trial.
A fluent Russian-speaker born to Soviet emigres and raised in New Jersey, Gershkovich moved to Moscow in late 2017 to join the English-language Moscow Times, and subsequently worked for the French news agency Agence France-Presse.
Since his detention, Gershkovich has appealed against his detention several times, appearing in the glass cages used for suspects in Russian courts. The appeals have been rejected.
His arrest shocked many Western news organisations and there are now almost no US reporters in Russia, which is ranked by the State Department as a hardship posting on a par with Freetown, Mogadishu, Damascus and Kabul.
The U.S. State Department has repeatedly told all U.S. citizens to leave Russia immediately due to "the potential for harassment and the singling out of U.S. citizens for detention by Russian government security officials".
