The Bataclan venue. Google Street View The first accounts are emerging from survivors of the hostage situation at the Bataclan venue in Paris.

"There was blood everywhere, there were bodies everywhere," said one witness, whom media reports identified as Marc Coupris and who said he was inside the hall.

Gunmen took hostages and began shooting them during the concert, in part of what appeared to be a series of coordinated terrorist attacks across Paris at seven different locations, French media is reporting.

France 24 reports that the police stormed the building at about 11:30 p.m. London time/12:30 Paris time, and two gunmen were killed. Hostages left the building, some running, some with hands on their heads. Some were shot from a balcony as they left, a witness told France 24. The attackers threw explosives at their victims inside the concert hall, France 24 reported.

Angelique Chrisafis, a Guardian reporter in Paris, talked to witnesses including Coupris, who went to the concert with a large group of friends:

"It was carnage," said Marc Coupris, 57, still shaking after being freed from the hostage-taking at the Bataclan concert venue. "It looked like a battlefield, there was blood everywhere, there were bodies everywhere. I was at the far side of the hall when shooting began. There seemed to be at least two gunmen. They shot from the balcony. Everyone scrabbled to the ground. I was on the ground with a man on top of me and another one beside me up against a wall. We just stayed still like that. At first we kept quiet. I don’t know how long we stayed like that, it seemed like an eternity. I saw my last final unfurl before me, I thought this was the end. I thought I'm finished, I'm finished. I was terrified. We must all have thought the same. Eventually, when a few gendarmes came in slowly we began to look up and there was blood absolutely everywhere. The police told us to run."

Another attendee said:

Jérome Boucer, shivering in the cold night wearing a white shirt splattered with the blood of the victims and wounded said: "The concert had started. I was in the audience and I heard what sounded like a fire-cracker. It was loud but the gig was very loud and I thought it was something that was part of the show. I think lots of people did too. Then they started firing. I saw what I thought was at least two people, then I fled. The exits were clearly marked and I just ran. There were wounded, there was a lot of blood. Blood everywhere."

A third:

"It was horrible, there were so many corpses, I just can't talk about it," said a bearded man in a death metal t-shirt as he ran down the street from the Bataclan in shock.

The Guardian has an excellent live blog with updates.

The police operation secured the building shortly before 1 a.m. Paris time / midnight London time.