A Russian security failure?

 https://www.reuters.com/world/europe/russian-security-failure-kremlin-says-no-country-is-immune-terrorism-2024-03-25/

Since Russia is in a state of war, one would think that they would be better prepared to handle internal violent situations.

https://en.wikipedia.org/wiki/Federal_Security_Service#Counterterrorist_operations

https://www.theguardian.com/world/2024/mar/24/did-ukraine-war-russian-security-services-neglect-islamist-threat-moscow

Of course if some group is very determined, they will keep looking for an advantage.

https://www.themoscowtimes.com/2024/03/24/russian-opposition-blasts-putins-broken-security-promises-after-moscow-attack-a84605

https://www.aljazeera.com/news/2024/3/25/fear-stalks-russia-after-moscow-massacre-as-putins-allies-play-blame-game

https://en.wikipedia.org/wiki/Federal_Security_Service#Creation_of_the_FSB

https://en.wikipedia.org/wiki/Federal_Security_Service#Role_in_Ukraine

https://thedigitallabyrinth.blogspot.com/search?q=the+Moscow+concert+hall+attack