The U.S. has said there is “no indication at this time” that Ukraine was behind the mass shooting at a concert hall in northwest Moscow on March 22 that has left at least 60 people dead and more than 140 injured.
Speaking at the White House, National Security Council spokesperson John Kirby said: “The images are just horrible and just hard to watch and our thoughts obviously are going to be with the victims of this terrible, terrible shooting attack."
He added there was "no indication at this time that Ukraine, or Ukrainians were involved in the shooting."
His comments drew an immediate response from the Kremlin, with Russian Foreign Ministry spokesperson Maria Zakharova demanding the U.S. hand over any information it had on the attack.
"On what basis do officials in Washington draw any conclusions in the midst of a tragedy about someone's innocence?" she said.
The terrorist group Islamic State (IS) later claimed responsibility for the attack in a Telegram post, and U.S. intelligence officials confirmed the claim.
Kateryna Denisova
The attack saw several gunmen opening fire at the Crocus City Hall ahead of a concert.
Images posted to social media showed them walking unchallenged through the venue and firing indiscriminately at those inside.
According to various estimates, several dozen or hundreds of people may remain in the concert building.
Just hours after the attacks began, former Russian President Dmitry Medvedev warned of retaliation against Ukraine if "terrorists of the Kyiv regime" were found to be behind them.
"If it is established that these are terrorists of the Kyiv regime, it is impossible to deal with them and their ideological inspirers differently," he wrote in a post on Telegram.
"All of them must be found and mercilessly destroyed as terrorists. Including officials of the state that committed such atrocity. Death for death."
Ukraine's military intelligence (HUR) said the attack was a "deliberate provocation by Putin's special services."
"This is a deliberate provocation by Putin's special services, about which the international community warned," a HUR spokesperson Andrii source 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.
Chris York
