Russia was too distracted trying to conquer Ukraine to notice ISIS-K gunmen slip into Moscow to massacre concertgoers, says Zelenskyy

• Russia was too busy trying to conquer Ukraine to notice ISIS-K gunmen slip into Moscow, said Zelenskyy.
• Ukraine's president said Russians now killing on Ukrainian land could have stopped the terrorists.
• Security analysts say Russia's security agencies dropped the ball when it came to ISIS-K.

The war in Ukraine distracted the Kremlin from ISIS-K's terror threat to Russia, Ukrainian President Volodymyr Zelenskyy said in his Saturday night address.

"Everything is absolutely predictable. Those hundreds of thousands of Russians who are now killing on Ukrainian land would surely be enough to stop any terrorists," he said.

The rampage at Crocus City Hall on March 22 killed at least 133 people. The four gunmen implicated have been detained, say Russian authorities.

Zelenskyy added, "If the Russians are ready to silently die in 'Crocus Halls' and not ask any questions to their security and intelligence agencies, then Putin will try to turn such a situation to his personal advantage again."

The US had warned the Kremlin several weeks beforehand that an attack on Russia was likely. 

The warning was partly based on intelligence that indicated an ISIS-K presence in Russia, two US officials told The Washington Post, but Putin dismissed the warnings, calling them "provocative."

ISIS-K, a branch of the Islamic State based in Afghanistan, claimed responsibility for the attack, but Putin has been focusing his attention on Ukraine.

He claimed the perpetrators "tried to escape and were moving toward Ukraine, where, according to preliminary information, a window was prepared for them from the Ukrainian side to cross the state border."

Kyiv rebuked the claims that the gunmen had links to Ukraine.

Moscow was a 'convenience' target for ISIS-K

Security analysts say Russia's security agencies dropped the ball when it came to ISIS-K because all their energy is focused on Ukraine.

Vera Mironova, an associate fellow at the Davis Center at Harvard University who studies Islamist terrorist movements in the former Soviet Union, told The Financial Times that Isis-K hit Moscow because the risk of capture was less.

"It's about the convenience of the target," she said.

Indeed, the militants had been planning to hit high-profile targets in Europe and develop their nihilistic presence beyond southwest Asia in December but were thwarted by Western security services.

Before Christmas, Germany was tipped off by a foreign intelligence agency of a potential plot to attack cathedrals in Cologne or Vienna by an ISIS-affiliate group, The Times reported.

On Saturday, Islamic State's official news agency, Amaq, bragged that the ISIS-K had killed a "large crowd of Christians," per The Telegraph.

But the Kremlin chose to ignore the threat from Islamic extremists.

Colin P. Clarke, an expert on domestic and transnational terrorism for The Soufan Group, a global security consulting firm, told The New York Times that "ISIS-K has been fixated on Russia for the past two years," adding that the group "accuses the Kremlin of having Muslim blood in its hands."