Russia Ukraine war, page-211249

Useful to make a note of the various claims (if it was Russia, as Ukrainian Intelligence claim, then the U.S. confirmation of ISIS responsibility becomes void I guess... and visa versa).
https://kyivindependent.com/ukraines-military-intelligence-calls-moscow-shooting-deliberate-provocation-by-putins-special-services/
Ukraine's military intelligence (HUR) has said a deadly shooting on a concert hall in Moscow on March 22 is a "deliberate provocation by Putin's special services. [...]
"This is a deliberate provocation by Putin's special services, about which the international community warned," Andrii Yusov, a spokesperson of Ukraine's military Intelligence, told Ukrainska Pravda.
In a post on its Telegram channel, HUR claimed the shooting is intended to justify "even tougher" attacks on Ukraine and total mobilization in Russia.
"The public execution of people in Moscow should be understood as Putin's threat of an even greater escalation and expansion of the war," HUR wrote.
The terrorist group Islamic State (IS) later claimed responsibility for the attack in a Telegram post, and U.S. intelligence officials confirmed the claim.