Russian intelligence foiled a terror attack on this week’s massive Victory Day memorial march in Moscow, a top Russian diplomat has said.
Around a million people marched through central Moscow on Wednesday in the annual Immortal Regiment rally, carrying pictures of family members killed during the Second World War.
President Vladimir Putin and visiting Israeli Prime Minister Benjamin Netanyahu joined the march on May 9, the day when Russia marks the end of the war.
Twenty people have been detained and 17 homes were searched as part of the investigation, he said.
The announcement came as Russia prepares to host the World Cup next month.
The FSB agency said four members of the suspected IS sleeper cell were detained in the Moscow region after they travelled from Novy Urengoi, an oil town in western Siberia.
The FSB said they plotted attacks in Moscow and were receiving orders from IS members in Syria via a messaging app.
Russia has been providing air cover for Syrian President Bashar Assad since 2015, while thousands of its own citizens went to Syria to join IS in fighting against Assad’s government.