MOSCOW  -  The Kremlin refused to comment Monday on the IS group’s claims that it was behind the deadliest attack in Russia in two decades, as rescuers searched for bodies amid the rubble of the burnt-out Moscow concert hall.

At least 137 people were killed when gunmen in camouflage stormed Crocus City Hall, shoot­ing spectators before setting the building on fire in the most fatal attack in Europe to have been claimed by IS group.

The group has said several times since Friday that it carried out the attack, and IS-affiliated media channels have published videos shooting concert-goers.

But in his only public remarks on the massacre, Russian Presi­dent Vladimir Putin on Saturday pointed to a possible Ukraine connection, and no senior Rus­sian official has commented on the IS claims.

“The investigation is still ongo­ing. No coherent version has yet been voiced,” Kremlin spokes­man Dmitry Peskov told report­ers on Monday when asked why Russia had not addressed IS’s claimed involvement.

“We are talking only about preliminary data. No version has been put forward yet,” he added.

Officials expect the death toll to rise further, as rescuers were searching the site for remains on Monday and 97 are still in hospi­tal. Putin has no plans to visit the site of the attack, on the north­western edge of Moscow, Peskov said. He will hold a meeting with Russia’s security chiefs, govern­ment officials and the heads of Moscow and the Moscow region later Monday.

The Kremlin also on Monday expressed confidence in the country’s powerful security agencies, as questions swirl over how they failed to thwart the massacre despite public and private warnings by the United States’ intelligence ap­paratus. “Special services are working tirelessly, dealing with all the threats, all the challeng­es facing our country and soci­ety,” Peskov said.

Putin, a former Soviet spy, headed the FSB briefly before becoming president and takes pride in its reputation as a team of feared intelligence operators.

A Moscow court has remanded four suspected gunmen in custo­dy on “terror” charges, accusing them of being the assailants who stormed the concert hall and then set it on fire on Friday night.

They face life in prison, though some Russian officials have called for the lifting of a mora­torium on the death penalty to deliver even harsher sentences. 

The Kremlin said Monday that it was not involved in discus­sions about possibly bringing back capital punishment.

In a series of late-night court hearings in Moscow that ran into the early hours of Monday, the four men -- with bruises and cuts on their swollen faces -- were dragged in amid dozens of reporters who had assem­bled at the capital’s Basmanny district court.

FSB officers wheeled one in to the hearing on a gurney, his eyes barely open. Peskov re­fused to comment on reports and videos on social media that showed bloody interrogations of the suspects after they were arrested on Saturday.

At least 137 people, includ­ing three children, were killed, according to the latest toll by Russian investigators. After walking through the theatre shooting spectators, the gun­men set fire to the building, trapping many inside.