Ukraine had 'no involvement' in Moscow attack: White House

Ukraine had "no involvement whatsoever" in the massacre in a Moscow concert hall that killed more than 130 people, the White House said Sunday, after Russian President Vladimir Putin suggested a Kyiv connection.

"ISIS bears sole responsibility for this attack. There was no Ukrainian involvement whatsoever," said White House National Security Council spokeswoman Adrienne Watson, using an acronym for the Islamic State group, which has claimed the attack.

There was "no" evidence that Ukraine was involved, agreed Vice President Kamala Harris in an interview with ABC News' "This Week" that was aired Sunday.

"ISIS-K is actually, by all accounts, responsible for what happened," she said.

The "K" refers to Khorasan, with the attack being claimed by IS's branch in Afghanistan and Pakistan.

At least 137 people were killed when camouflaged gunmen stormed the Crocus City Hall, in Moscow's northern suburb of Krasnogorsk, and then set fire to the building on Friday evening.

The Islamic State group on Saturday wrote on Telegram that the attack was "carried out by four IS fighters armed with machine guns, a pistol, knives and firebombs," as part of "the raging war" with "countries fighting Islam."

A video lasting about a minute and half apparently shot by the gunmen has been posted on social media accounts typically used by IS, according to the SITE intelligence group.

Putin has vowed to punish those behind the "barbaric terrorist attack" -- but in his only public remarks on the massacre he made no reference to IS's claims of responsibility.

Instead he said four gunmen trying to flee to Ukraine had been arrested.

"They tried to escape and were travelling towards Ukraine, where, according to preliminary data, a window was prepared for them on the Ukrainian side to cross the state border," he said in a televised address to the nation on Saturday.

Kyiv has strongly denied any connection, with Ukrainian President Volodymyr Zelensky accusing Putin of trying to shift the blame onto them.

IS-K is a Sunni militant group that emerged from Afghanistan's eastern Nangarhar province around 2015, and hopes to install a hardcore Islamic caliphate spanning India, Iran and Central Asia.

The group has carried out dozens of attacks in Afghanistan and Pakistan. Under the Taliban, which regards it as an enemy, analysts say its efficacy inside Afghanistan has been eroded -- but that in recent months it has stepped up its activities globally.