Moscow Crocus City Hall (Крокус Сити) attacked by terrorists, on fire

Moscow Crocus City Hall (Крокус Сити холл) attacked by terrorists, on fire.
Several people in camouflage opened fire with automatic weapons on the ground floor of the Crocus City Hall, Moscow.
They threw a grenade or an incendiary bomb, which started a fire.
About 100 people were escorted out of Crocus by firefighters, reports the Moscow region headquarters of the Ministry of Emergency Situations.
An operation is underway to rescue people from the roof of the building.
The Crocus City Hall is a music venue.
US embassy in Moscow hinted at upcoming terrorist attack one month before Crocus Hall shooting.
The White House commented on what happened at Moscow's Crocus City Hall: The United States is aware of reports of the shooting, considers the footage from the scene “horrifying”