Russia pointed the finger at Ukraine after the worst terrorist attack in Moscow for more than two decades killed at least 115 people, even as Islamic State claimed responsibility.

The Federal Security Service said Saturday that four suspects were detained in Russia’s Bryansk region following the assault by gunmen with automatic weapons against people attending a rock concert at the Crocus City Hall on the edge of the capital.

They planned to cross the border into Ukraine where they “had contacts”, the service known as the FSB said in a statement without giving more detail, the Interfax news service reported.

Ukraine has denied any role, calling Friday’s attack a false-flag operation by the Kremlin. SITE, an organisation which tracks jihadist channels, reported that Islamic State had claimed the attack in a Telegram post. Bloomberg News wasn’t immediately able to confirm the claim.

Russian President Vladimir Putin hasn’t appeared in public or commented so far. FSB Director Alexander Bortnikov reported to him that 11 people, including the four suspects were detained, according to a Kremlin statement Saturday.

Russia’s Investigative Committee said Saturday the death toll rose after officials found more victims at the site of the attack. Officials earlier said at least 145 people had been wounded. Fire ripped through the massive venue after explosions were heard during the assault at Crocus City Hall, leading to a partial collapse of the roof.  

It’s the biggest single loss of life from terrorism in Moscow since Chechen separatists took hostages in 2002 at the Nord-Ost theatre. At least 170 people including the dozens of attackers died during a botched rescue mission.

At a meeting with senior FSB officers on Tuesday, Putin hit out at “frankly, provocative statements” by Western officials this month warning of a possible imminent terrorist attack. “All this resembles outright blackmail and the intention to intimidate and destabilise our society,” the president said.

The US Embassy in Moscow issued a public warning on its website on March 7 that “extremists have imminent plans to target large gatherings in Moscow, to include concerts”.

While the US didn’t say specifically that the warning was related to the attack, National Security Council spokesperson Adrienne Watson said in a statement late Friday that “the US government had information about a planned terrorist attack in Moscow”.

“The US government also shared this information with Russian authorities in accordance with its longstanding ‘duty to warn’ policy,” she added.

The assault took place days after Putin cemented his grip on Russia by claiming a fifth term with 87% of the vote in the presidential election. He was monitoring developments closely, the Kremlin said late Friday. Authorities cancelled public events and tightened security in cities across the country.

The FSB said earlier this month it had prevented an attack on a Moscow synagogue by what it called an Afghan branch of Islamic State, Interfax reported.

Friday’s bloody assault was a throwback to an earlier period of Putin’s quarter-century rule, when suicide bombings, most blamed on Islamists from within Russia or its neighbours, killed scores of people. It shattered the illusion of security in Moscow that Putin has sought to cultivate in the more than two years since he invaded Ukraine.

Islamist groups have targeted Russia in the past citing what they call anti-Muslim policies by the Kremlin. The seizure of a school in Beslan in the south of the country led to more than 330 fatalities, many of them children, in 2004. In 2010, twin suicide attacks in Moscow subway stations killed at least 40, while a suicide bombing killed 16, including the attacker, in the St Petersburg subway in 2017.

President Joe Biden was being updated on the events Friday, according to the White House. There was no indication of Ukrainian involvement, spokesman John Kirby said.

Moscow has been largely insulated from the direct effects of Putin’s February 2022 invasion of Ukraine, which his spokesman Dmitry Peskov called “a state of war” for the first time on Friday. He later walked back the comment.

“The obvious route for the Kremlin to spin this is that it’s something to do with the war in Ukraine,” said Charles Lichfield, deputy director of the Atlantic Council’s GeoEconomics Center in Washington. “The immediate response could be more drone attacks and ballistic attacks, but they already increased before the terrorist attacks.”

Moscow’s forces have stepped up missile strikes against Ukrainian cities and infrastructure in recent weeks, killing dozens of civilians. Early Friday, it unleashed the biggest missile and drone assault on Ukraine so far this year, focused on energy infrastructure.

At the same time, Ukraine has mounted a campaign of strikes inside Russia with its troops struggling on the battlefield amid delays in vital aid from the US and other allies. Drones have hit factories and oil refineries, while attackers in border regions have staged raids. 

  - Bloomberg