Russian Foreign Ministry spokeswoman Maria Zakharova said on Wednesday that it was "extremely hard to believe" that the IS terror group would have had the capacity to launch an attack on a Moscow concert hall last Friday that killed at least 143 people.
Zakharova repeated Moscow's assertions, for which it has not yet provided evidence, that Ukraine was behind the attack on the Crocus City Hall, the deadliest Russia has suffered in 20 years.
Russia's Emergencies Ministry published a list of names showing 143 people had died in last Friday's mass shooting. Earlier official tallies had put the death toll at 139.
The IS has claimed responsibility for the massacre and US officials say they have intelligence showing it was carried out by the network's Afghan branch, IS Khorasan.
Ukraine has repeatedly denied it had anything to do with the attack.
But Zakharova said the West had rushed to pin responsibility on the IS as a way of deflecting blame from Ukraine and the Western governments that support Kyiv. "In order to ward off suspicions from the collective West, they urgently needed to come up with something, so they resorted to ISIS, pulled an ace out of their sleeve, and literally a few hours after the terrorist attack, the Anglo-Saxon media began disseminating precisely these versions," she said.
Russian President Vladimir Putin has said the attack was carried out by militants but has suggested it was to Ukraine's benefit and that Kyiv may have played a role.
He has said that someone on the Ukrainian side had prepared a "window" for the gunmen to escape across the border before they were captured in western Russia on Friday night.
On Tuesday, however, Belarusian leader Alexander Lukashenko said the gunmen had initially sought to cross into his country before turning away and heading towards Ukraine once they realised that crossings into Belarus had been sealed.
The director of Russia's FSB security agency said on Tuesday that he believed Ukraine, along with the US and Britain, were involved in the Moscow attack.
British Foreign Secretary David Cameron responded on social media platform X, saying: "Russia's claims about the West and Ukraine on the Crocus City Hall attack are utter nonsense."
The head of Ukraine's Main Intelligence Directorate, Kyrylo Budanov, told a security conference in Kyiv he believed Russian authorities had known about preparations for a major attack since at least mid-February.
Budanov, whose comments were reported in Ukrainian media, said authorities chose to say nothing either because they underestimated the scale of the attack, or to pin the blame on Ukraine and proceed with the dismissal of officials.
After the shooting, a US official said Washington had warned Moscow in recent weeks of the possibility of an attack.