Russia’s Federal Security Service said 40 people died and more than 100 were wounded in an attack Friday at a Moscow concert hall. The attack, which Russian authorities are investigating as terrorism, is the deadliest in Russia in recent years. Several gunmen burst into the concert hall on the edge of Moscow and sprayed visitors with automatic gunfire, killing and wounding dozens and starting a massive blaze. Russian media reported that the venue's roof was collapsing. The attack comes days after President Vladimir Putin cemented his grip on the country in a highly orchestrated electoral landslide. Russian news reports said that the assailants threw explosives, triggering the massive blaze. Video posted on social media showed huge plumes of black smoke rising over the building, which can accommodate more than 6,000 people. The attack took place as crowds gathered for performance by Picnic, a famous Russian rock band. Russian news reports said that visitors were being evacuated, but some said that an unspecified number of people could have been trapped by the blaze. Read the full story: https://www.9news.com/article/news/nation-world/moscow-russia-concert-hall-shooting-explosion-crocus-city-hall/507-b00c6594-3499-4d90-99de-d4d0319a4cf1 More local videos here: https://bit.ly/2Pa0d1l Subscribe to NEXT: http://bit.ly/2eP1GwI Stay connected: 9NEWS Website: http://www.9news.com/ Facebook: https://www.facebook.com/ilike9news Twitter: https://twitter.com/9NEWS Instagram: https://www.instagram.com/9newsdenver/ Download the 9NEWS App: https://www.9news.com/appredirect/ Sign up for the 9NEWSLETTER: https://www.9news.com/email 9NEWS (KUSA) is located in Denver, Colorado.