The federal investigation agency said it was investigating the incident as a terrorist attack, while the Federal Security Service said more than a hundred other people had been injured. Moscow Mayor Sergei Sobyanin called the events at the Crocus City Hall concert venue in Krasnogorsk, outside Moscow’s city limits, a “horrible tragedy.”

Video carried on Russian Telegram channels showed gunmen pacing across the theater’s bright foyer with people lying in pools of blood. Other videos showed people ducking, with the sound of gunfire in the background. The Wall Street Journal couldn’t independently confirm the footage.

The state news agency TASS also reported an explosion at the venue, where it said part of the complex was engulfed in flames and black smoke was seen billowing into the sky. In a message posted on Telegram on Friday, Foreign Ministry spokeswoman Maria Zakharova said, “The entire world community is obliged to condemn this monstrous crime.”

Gunmen open fire at Crocus City Hall, in Krasnogorsk, Moscow region, Russia, March 22, 2024, in this still image obtained from a video. Video obtained by Reuters/via REUTERS

Moscow has canceled all concerts and mass gatherings scheduled for the weekend, the mayor, Sobyanin, said. Two other regions close to Krasnogorsk also canceled events as Russia’s special operations teams, national guard and fire squads had been deployed to the theater complex, one of the Moscow area’s biggest venues.

Putin’s spokesman said the Russian leader was receiving constant updates and was coordinating the response to the attack, TASS reported.

Tickets for the concert, featuring art rock band Picnic and which was scheduled for 8 p.m. local time, had been sold out, according to ticket retailers, in a venue that had thousands of seats.

Witnesses told RIA Novosti that the attackers burst into the concert hall and began shooting people at point-blank range and throwing smoke bombs.