Russia's counter-terrorism agency says it has arrested a group of people who were preparing to carry out an attack in Moscow.
The National Anti-Terrorism Committee said in a statement that homemade explosives were found in an apartment in the capital where the group were arrested.
No details about the number or identity of the suspects were given.
Russian news agencies, citing law enforcement sources, said more than 100 residents in the building were evacuated during the raid and supplies of natural gas were cut off during the operation.
Russia's decision to launch airstrikes in Syria has led to warnings the move could encourage Islamic extremists to target the country and make it easier for them to recruit Russian Muslims.
Russia says 2,400 of its citizens have joined Islamic State, which controls large parts of Iraq and Syria.
