Russia says Ukraine gave refuge to fleeing Islamic State terrorists after Moscow concert attack

Russia on Friday (May 24) said that Islamic State executed the March concert hall attack in Moscow in coordination with unnamed entities in Ukraine. The terror attack which killed over 140 people was the deadliest attack on civilians in Russia in two decades.

"In the course of the investigation... it has been established that the preparations, the financing, the attack and the retreat of the terrorists were coordinated via the internet by members of Khorasan Province (IS-K)," an IS branch active in Afghanistan and Pakistan, Alexander Bortnikov, the head of FSB, was quoted as saying by the RIA Novosti news agency.

The Islamic State has claimed responsibility on multiple occasions for the March 22 attack but Moscow linked Ukraine and the West with the attack.

Bortnikov, while delving upon the Ukrainian angle in his statements on Friday (May 24), said that "upon completing the attack, the terrorists received clear instructions to move toward the Ukrainian border, where from the other side a 'window' had been prepared for them."

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"The investigation is ongoing, but it is already safe to say that Ukrainian military intelligence is directly involved in this attack," the state news agency quoted Bortnikov as saying.

Ukraine has denied any involvement in the incident.

Moscow concert attack: What happened?

Terrorists stormed the Crocus City Hall venue on the outskirts of Moscow before setting the building on fire in March killing over 140 people.

More than a dozen suspects have been arrested including the four assailants, who are all from the Central Asian nation of Tajikistan, a former Soviet republic on Afghanistan's northern border.

The United States has said it had publicly and privately warned Russia in early March that terrorists were planning an attack on a concert hall in Moscow.

A number of unnamed US intelligence officials told the US media outlets after the massacre that they had told Moscow it was the Crocus City Hall specifically that IS was planning to attack.

(With inputs from agencies)