I just want to take you to the scene live in Moscow as you get a sense of the emergency services still in attendance. It's very difficult to get a clear picture of exactly what is going on there tonight. Earlier, reports suggested some of the gunmen were still inside that building and a number of concert goers still trapped in there. Now, reports from the TASS news agency suggesting that some were able to make their way out through the basement and then into the underground lines to be able to evacuate from that building. But we also know that large parts of the building were on fire and reports suggesting the roof or certainly part of the roof had collapsed. They're giving you a sense of the emergency services still in attendance at that concert hall. But there's a lot of misinformation. There's a lot being shared on social media right now. To make sense of it, our BBC Verify team have been checking the footage that has been shared online.

Now, people have been filming the dramatic events on their phones and posting them on social media channels. Let me show you what we've been looking at. Now, this video begins as people start leaving the hall and something appears to have gone very wrong. You suddenly hear gunshots and people running. It's difficult at this point to know how many people are involved in this incident, but in this video, you can see many people in the hall. Now, screens begin to ring out and people can be seen shouting, Close the door. And people then begin to fall onto the floor, hiding behind the chairs. Then gunshots continue to be heard inside the hall. As you can see, there are scenes of panic and people trying to escape. Now, here's another video we verified. This is from outside the hall, and you can see that there's a significant part of the building on fire with plumes of smoke rising. And we've seen another video from a different angle, again, showing from the outside of the building, again, on fire. Now, witnesses have said that the shooting started in the foyer. We've also seen another video with four gunmen, which is too graphic to show you.

In it, you can see people shooting with several casualties on the floor. And it's worth noting that a few weeks ago, the US Embassy in Moscow had issued a warning for people to avoid crowded places in the capital city. Now, we've also seen reports of another explosion inside the hall, and that some of the gunmen have barricaded themselves inside. As I said, this is a developing news story, we'll continue to verify more footage as we get it.