Russia says for the first time that ISIL coordinated the concert hall assault in Moscow, in which more than 140 people died.

ISIL has claimed responsibility on multiple occasions for the March 22 attack, but Russia has repeatedly tried to link Ukraine and the West to the attack.

FSB chief Alexander Bortnikov was quoted as saying by the Ria Novosti news agency on Friday that “preparations, the financing, the attack and the retreat of the terrorists were coordinated via the internet by members of Khorasan Province [ISKP or ISIS-K],” an ISIL branch active in Afghanistan and Pakistan.

Bortnikov did not discard the Ukrainian angle in his statements on Friday, for which it has not provided evidence, saying 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.”

“The investigation continues, but it can already be said with certainty that Ukrainian military intelligence is directly implicated in the attack,” he said.

Kyiv has dismissed the allegation as absurd.

Four attackers shot concertgoers at the Crocus City Hall near Moscow on March 22 and then set fire to the venue, in the deadliest attack in Russia in 20 years.

While pointing the finger at Ukraine, Bortnikov also said, according to Russian news agencies, that the preparation, financing, the actual attack and the attempted flight of the gunmen were coordinated over the internet by ISKP.

Andriy Yusov, spokesperson for Ukraine’s military intelligence agency, said on national television on Thursday, “Russian propaganda did not forget about the Crocus story. It will continue trying to promote the absurd point about Ukraine’s alleged complicity even though it can’t stand up to any criticism and it’s completely illogical.”

The suspects held by Russia include the four suspected gunmen, all citizens of Tajikistan, whose detention was extended last week until August 22. No date has been set for their trial.

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

Unnamed US intelligence officials told US media outlets after the killings that they had told Moscow it was the Crocus City Hall specifically that ISIL was planning to attack and that Russia dismissed those warnings.

Just three days before the attack, President Vladimir Putin accused Washington of “blackmail” and trying to “intimidate” Russians.