Russia's Investigative Committee said that Islamic State (IS) fighters were behind an attempted attack on a mosque in a Siberian town in 2014.
It said on October 15 that it had completed its investigation into the incident and had submitted a criminal case against two men to a court.
The committee linked the two men to IS and said they had plotted a terrorist attack against the mosque in Pyt-Yakhin in the Khanty-Mansi autonomous area.
Vladimir Markin, spokesman for the investigative committee, identified one of the men as Valeh Amiraliyev, an Azerbaijani, and said he is in Ukraine.
Russia has asked Ukraine to extradite the suspect, but Ukraine has not responded, he said.
Amiraliyev was detained at the Kyiv airport in Ukraine last month after Russia put him on Interpol's wanted list.
He is said to have close ties with Vugar Padarov, an organized crime figure who was accused of planning a series of attacks in Azerbaijan on the eve of the Eurovision 2012 song contest.
Padarov was killed in a shootout with Azerbaijani police that year.