Russian officials said at least 40 people were shot to death and more than 100 others were injured in an apparent terrorist attack at a large concert hall in suburban Moscow on Friday evening, NBC News reported.

The report said the attack took place right when the crowd gathered for a concert of the Russian rock band Picnic at the Crocus City Hall, a venue capable of hosting more than 9,000 people.

Videos shared on social media showed armed men in what appeared to be camouflage firing multiple rounds at screaming civilians, including women. Russian state media reported there were at least three attackers.

Several people were seen lying in pools of blood outside the concert hall.

Other videos showed the venue on fire after an explosion.

According to the Russian news source Meduza, evacuation procedures were underway, but some people could have been trapped in the burning building.

Andrei Vorobyov, governor of the Moscow region, said 70 ambulance teams were operating in the vicinity of Crocus City Hall.

Moscow Mayor Sergei Sobyanin announced that all large-scale sporting, cultural and other public events would be canceled in the city this weekend, Reuters reported.

According to The Associated Press, no group or individual immediately claimed responsibility for the attack.

Mykhailo Podolyak, an adviser in the office of Ukraine President Volodymyr Zelenskyy, said in a post on social media that Ukraine, which is at war with Russia, “certainly has nothing to do with the shooting/explosions in the Crocus City Hall.”

According to BBC News, Russian Foreign Ministry spokeswoman Maria Zakharova urged the international community to condemn the incident, describing it as “a monstrous crime.”

John Kirby, spokesman for the U.S. National Security Council, said the images of the shooting were “horrible and hard to watch,” according to the AP.

“Our thoughts are going to be with the victims of this terrible, terrible shooting attack,” Kirby said. “There are some moms and dads and brothers and sisters and sons and daughters who haven’t gotten the news yet. This is going to be a tough day.”

On March 7, two weeks prior to the attack, the U.S. Embassy in Moscow issued a warning regarding an imminent threat of a terrorist attack in Russia’s capital.

Russian President Vladimir Putin dismissed the warning as an attempt to intimidate his country.

This article appeared originally on The Western Journal.