Moscow concert hall attack: White House says 'thoughts with victims of shooting' – video

White House National Security Council spokesperson John Kirby has said the 'images of the attack were just horrible and just hard to watch'.

At least 40 people have been killed and more than 140 wounded, according to unofficial reports, in the worst terror attack in Russia in years, as gunmen in combat fatigues opened fire and detonated explosives in a major concert hall on the outskirts of Moscow.

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