The Moscow City Court has ruled that the pretrial detention of a Kazakh citizen suspected of involvement in a plot to kill Russian President Vladimir Putin was legal.
Ilya Pyanzin's pre-trial detention was prolonged last month until January 25, 2013.
Pyanzin was detained in Ukraine in February.
His detention led to the arrest of the alleged mastermind of the plot; ethnic Chechen Adam Osmayev, whose extradition from Ukraine to Russia was halted at the request of the European Court for Human Rights.
Pyanzin, who denies any wrongdoing, was extradited to Russia in August.
Reports about the alleged plot to kill Putin surfaced days before Russia's March 4 presidential election, prompting skeptics to say it was fabricated and timed to boost Putin's popularity before the vote.
Based on reporting by Interfax and RIA-Novosti