Armed gunmen attacked a concert hall and shopping center in Moscow on Friday in an apparent terrorist attack.

Russian state media reported that at least three gunmen armed with automatic weapons and incendiary explosives entered the hall. Unconfirmed videos on social media appeared to depict the men shooting into groups of civilians at close range.

At least 80 people were killed and more than 100 injured in the attack, according to the Russian FSB security, one of the KGB’s successors. More than 50 ambulance crews have reportedly been dispatched to the scene.

Islamic State claimed credit for the attack, posting on Telegram that its “fighters attacked a large gathering of Christians in the city of Krasnogorsk on the outskirts of the Russian capital, Moscow, killing and wounding hundreds and causing great destruction to the place before they withdrew to their bases safely.”

The U.S. embassy issued a warning earlier in March that it was monitoring reports that “extremists have imminent plans to target large gatherings in Moscow,” including concerts.

Russia has frequently been the target of Islamist terrorism, including the 2002 Moscow theater siege in which 40 Chechen terrorists took 850 hostages. Ultimately, 132 of the hostages were killed and hundreds injured.

John Kirby, White House national security communications advisor, said at a press briefing Friday that the U.S. condemned the attack.

“The images are just horrible and hard to watch,” Kirby said. “Our thoughts obviously are going to be with the victims of this terrible shooting attack.”

Image - Russian Embassy - Video - Visegrad