Death toll in Moscow concert hall attack rises to 133; suspected gunmen arrested

March 22 (UPI) -- The death toll from the deadly attack at Crocus City Hall near Moscow rose to at least 133 on Saturday as security official reported 11 suspects have been arrested in connection with the assault.

Russia's Investigative Committee provided the updated death toll to state media as investigators ramped up a probe into the terrorist attack on the complex in Krasnogorsk, one of Russia's biggest shopping and entertainment centers, with the toll expected to rise further.

Some 107 victims of the attack remained hospitalized in and around Moscow on Saturday, Deputy Russian Prime Minister Tatyana Golikova told reporters.

Officials said several gunman opened fire with automatic weapons, shooting people at point-blank range at the complex while also throwing incendiary bombs which exploded and started a fire in the concert hall before a scheduled event.

Hours after the attack, a branch of ISIS based in Syria released a statement claiming its fighters caused "major destruction" in a "big gathering for Christians in the Russian Moscow suburb."

The popular rock band Picnic was scheduled to play at a sold-out show.

Alexander Bortnikov, director of Russia's FSB internal security agency, told Russian President Vladimir Putin on Saturday that 11 people people had been arrested, "including all four terrorists directly involved" in the assault, the Kremlin announced.

Bortnikov also told Putin agents are working to identify the ring of accomplices who aided those who committed the terrorist attack.

The Russian leader declared Sunday to be national day of mourning during a televised address. In his speech, he noted that "dozens of victims," including children, were still fighting for their lives.

Putin said the four detained men thought to the be perpetrators had "tried to hide and moved towards Ukraine" before their capture, where "a window was prepared for crossing the state border."

"Special security measures" had been introduced throughout the country to prevent Islamic militants from carrying out more terrorist acts, he declared.

Russian emergency officials said firefighters had evacuated about 100 people from the basement of the building and were attempting to rescue others trapped on the roof, which was beginning to collapse.

More than 320 firefighters and 130 emergency vehicles have responded to the crisis, with three emergency helicopters dumping water on the fire.

U.S. National Security Council spokesman John Kirby said the White House was working to gather more information on the attack.

"Our thoughts obviously are going to be with the victims of this terrible, terrible shooting attack," he said.

The White House said it found "no indication at this time" of Ukraine's involvement in the attack.

Mykhailo Podolyak, an aide to Ukrainian President Volodymyr Zelensky, said in a post on X that "Ukraine absolutely has nothing to do with these events."

"Ukraine has been fighting with the Russian army for more than two years. And everything in this war will be decided only on the battlefield," the post read.

The U.S. State Department issued a notice to Americans in Moscow to avoid larger gatherings and to stay in contact with the State Department for further updates.

Moscow's mayor Sergei Sobyanin called the shooting a "terrible tragedy" and canceled all "sports, cultural and other mass events" for the weekend in response to the attack.

Public events also were canceled in nearby Podolsk and in the annexed Kherson region of Ukraine.

Yulia Navalnaya, widow of Russian opposition leader Alexei Navalny, who died last month in prison, took to X to offer her condolences to the victims of the attack.

"What a nightmare in Crocus," her post read. "Condolences to the families of the victims and quick recovery to the injured. Everyone involved in this crime must be found and held accountable."

Russian Foreign Ministry spokesperson Maria Zakharova called on the international community to "condemn this monstrous crime."

Officials from France, Germany and the United Kingdom have condemned the attack, with the German Foreign Office on X calling for the incident to be "investigated quickly."

"Our deepest condolences with the families of the victims," the post read.

The U.K. Russian Embassy called the shooting "a terrible tragedy," and gave condolences to "families and friends of those affected and killed by today's events."

France's foreign ministry said in a statement, "The images reaching us from Moscow are terrible. Our thoughts are with the victims and injured and the Russian people. Full light must be shed on these heinous acts."