Concert-goers and witnesses have described the chaos after “huge bomb-like bangs” went off in Manchester Arena following an Ariana Grande gig.

One fan at the concert with his sister described how the apparent explosion hit the venue as they were leaving the building.

Majid Khan, 22, said: “I and my sister, along with a lot of others, were seeing Ariana Grande perform at Manchester Arena, and we were all exiting the venue when a huge bomb-like bang went off that hugely panicked everyone and we were all trying to flee the arena.

“It was one bang and essentially everyone from the other side of the arena where the bang was heard from suddenly came running towards us as they were trying to exit Trinity Way and that was blocked so everyone was just running to any exit they could find as quickly as they could.

“Everyone was in a huge state of panic, calling each other as some had gone to the toilet whilst this had gone off, so it was just extremely disturbing for everyone there.”

Ariana Grande had just left the stage (John Salangsang/Invision/AP, File)

Emergency services outside the arena (Peter Byrne/PA)

There was a heavy police presence outside the scene (Peter Byrne/PA)

Footage posted online by one concert-goer shows fans filing out of the building while an announcer attempts to maintain calm.

The voice can be heard saying: “Ladies and gentleman, please take your time, there’s no need to bunch up, there are no problems here – just take your time and keep exiting the building.”

A barman at the nearby Steven Charles Snooker Club, who gave his name as Tyler, said he saw people lying on the ground covered in blood.

Another ambulance arrives at the arena in Manchester. pic.twitter.com/5SSECArOVx — Patrick Hurst (@paddyhurst) May 23, 2017

“We’ve had a few people in with panic attacks and in all kinds of disarray,” he told Press Association. “There was a gentleman on the floor with his leg all bleeding and woman with blood down one side of her face.

“We felt something but didn’t know what it was – there was a sound like thunder. One girl had a panic attack and another had streaming tears, a woman had a heart attack just outside. It’s a lot of teenagers – they’re all in tears.”

Suzy Mitchell, 26, whose flat is opposite the venue, reported a huge bang rocking the neighbourhood.

Heard the huge bang from my bed. Loads of people running away screaming down the road?! #manchesterarena pic.twitter.com/zpoKhl39Zm — Snooz 🤡 (@Suzymoonbeam) May 22, 2017

She told the Press Association: “(I) just heard a huge bang from my bed, came out to the front of my apartments (we’re on the top floor so have perfect view) and everyone was running away in big crowds.”

Liverpool City Region metro mayor Steve Rotheram tweeted: “My 2 daughters caught up in the Manchester explosion at the arena. They are thankfully safe, but I fear for others.”

Confirmed deaths at the Manchester arena. Feel sick to think that people have lost their lives at a gig attended by so many young people. — Steve Rotheram (@MetroMayorSteve) May 22, 2017

I've spoken with @AndyBurnhamGM to offer our city regions full support and solidarity to the terrible events in Manchester tonight. — Steve Rotheram (@MetroMayorSteve) May 22, 2017

He posted later: “All my thoughts go out to those parents waiting to hear of the safety of their children. It’s a parents worse nightmare. So, so sad.”

A family from Newcastle said they were missing two family members and had been unable to contact them.

A middle-aged woman said her partner, aged 32, and daughter, 19, were outside the arena to pick up her younger daughter who attended the concert. She said: “There was a bang, a massive explosion”. They have not been seen or heard of since and are not answering their phones.

Jane Pearson, who was at the gig in Manchester with her daughter.@PA pic.twitter.com/6NrbXPTKU8 — Patrick Hurst (@paddyhurst) May 23, 2017

Another man who took his daughter to the gig said: “Ariana said: ‘Bye bye Manchester!’ The lights came on then there was two big noises and people started running and shouting.

“We got in a lift to go up to the next floor to the exits. When the doors opened I saw blood on the floor and two injured people. Blood all over their faces. A lot of people were in shock.”

Anthony Senior dashed over from Bradford to be re-united outside the arena with his wife and two daughters who had been at the concert.

His wife and one daughter were in an ambulance being treated for cuts and bruises.

His other daughter Amelia, aged 11, said: “We ended up leaving early because everyone had gone off the stage. We walked out, we’d gone through the gates to actually go out, suddenly something really hot just flew over us and behind me and my sister and we all dropped to the floor. I couldn’t really hear anything it was just really scary.”

Mr Senior said: “We’re the lucky ones. I think they have got a lot more serious things to contend with.”