A terror attack at a concert venue in Russia left 60 people dead and 100 more injured over the weekend, Russian media reported.

According to the New York Times, the popular Russian band Piknik was set to perform a sold-out show at Crocus City Hall at 8 p.m. on Friday, March 22 when a group of gunmen carried out a terror attack. Videos on social media show gunmen entering the venue and opening fire on people in the lobby of the concert hall, and during the attack, smoke and fire was seen outside the venue.

TASS, the state news agency, reported that emergency services had dispatched helicopters to try to rescue people from the building’s roof — where flames burst into the sky. Russia’s emergency service reported it sent 130 vehicles to the scene, as well as three helicopters, which dropped water onto the fire.

ticketflipping provides valuable tools for ticket resale professionals

The attack left at least 133 people dead, the publication reported, while more than 100 people were injured. U.S. officials believe that the attack was brought-on by the Islamic State in Khorasan, or ISIS-K.

The U.S. Embassy in Moscow reportedly issued a security alert on March 7 that warned that its personnel were “monitoring reports that extremists have imminent plans to target large gatherings in Moscow, to include concerts.”

This is a developing story.