This is N. B. C. Nightly News with Jose Diaz-Billard.

Good evening. The United States tonight is condemning the terror attack in Moscow.

The death toll there sits at 133 and is likely to grow even higher. It happened at a popular

concert horror there, gunman storming the complex killing civilians before

setting the place on fire.

Authorities have detained nearly a dozen people,

including four people, they say,

carried out the act of terrorism themselves.

An offshoot of the terror group ISIS is taking credit. It's the same group that has

targeted Americans before, killing 13 US troops during the chaotic evacuation from Afghanistan

three years ago. But when Vladimir Putin addressed the nation today,

he placed a blame elsewhere. Mount Bradley is covering it all for us tonight and a warning.

The video you are about to see is disturbing.

Tonight Moscow still smolders as the death toll from Friday night's terror attack

continues to climb. At least 133 people were killed and hundreds more injured after as

many as four gunman attacked a packed house at this concert hall. Shooting automatic weapons, throwing bombs, and dousing the building in flammable chemicals.

This video showing gunman opening fire on victims even as they huddled on the ground.

I honestly thought it was a firecracker, said this witness, but these crackles, they were...

They weren't stopping.

There was screaming, panic.

At least some of the gunman were able to flee,

but Russian authorities say everyone has since been caught.

...