Russia has said it thwarted attempted drone attacks and attacks on supporters by groups of ultras at the World Cup.
Alexander Bortnikov, the head of Russia's Federal Security Service, said officers "took measures to detect and foil attempts by terrorists to use drones during the preparation and hosting of various major political and sports events, most of all during the soccer World Cup."
Bortnikov offered no further details in his comments, which were reported by Russia's Tass state news agency.
Russia used thousands of police officers along with cutting-edge surveillance technology at the World Cup. However, four Pussy Riot protesters were able to run onto the pitch during the final.
Tass reported that planned attacks on foreign fans by ultras had been foiled, according to Interior Minister Vladimir Kolokoltsev.
"The actions of seven nationalist football hooligan gangs plotting attacks on fans from Senegal, Argentina, the UK and Poland were thwarted thanks to the timely exchange of information during the preparations for the World Cup," Kolokoltsev said.
The minister added that Russia had prevented 3,000 people from entering the country during preparations for the World Cup and the duration of the tournament.