At least 60 people have been killed after gunmen attacked a packed concert venue on the outskirts of Moscow.
More than 100 were wounded at the Crocus City Hall, according to the FSB Federal Security Service.
The US says an Islamic State group claim of responsibility is credible. Russia has not commented.
Dramatic video shows panicked concertgoers taking cover as shots and explosions ring out.
A large fire engulfed the roof of the complex and Russia’s national guard is searching for the gunmen.
The White House says it is working to find out more about the situation and Ukraine has denied any involvement in the attack.