The Crocus City Hall in Krasnogorsk, a suburb to the north-west of Moscow, is known to host several thousand people and has hosted top international artists.

Video on social media showed several armed men entering the lobby before they opened fire.

The attack took place before the start of a concert by Picnic, a popular rock band that previously said on Instagram that it had sold out the venue.

Up to 6,200 tickets had been sold for tonight’s gig, according to Russian media, but we don’t yet know exactly how many people were inside at the time of the attack.

Russian media outlets also reported that members of the band were not harmed during the shooting.