Andy was in the foyer near the entrance to the arena, waiting for his wife and daughter.

He told BBC 5 live the scene was "like something out of a war film". He said he was thrown to the ground by the force of the explosion.

"When I get up and look round, there’s just bodies everywhere. I reckon 20-30 bodies. I can’t say if some of them were dead but they looked dead.

"They were covered in blood and were really seriously hurt.

"The first thing I did was I ran into the arena trying to find my family. I couldn’t find them so I pulled back to where everyone was injured to physically look at people to see if it was my family.

"At the same time I started helping the emergency services as best I could while I was trying to get hold of my family."

He found his family, who were safe, but said there were "kids and teenagers just lying there screaming".

BBC Radio 5 live

Eyewitness Jessica, said: "It was shocking. Like I just heard this massive bang and then everyone just started running towards us screaming and crying.

"Everyone just trampled over us just to get out.

"I was shocked I didn't know what was going on. Everyone was sprinting so we were just getting stamped on and everything."

In the last few moments, the controlled explosion for the second suspect device has taken place.

The capacity of the Manchester Arena is about 18,000 but it is not clear how many people had tickets to Ariana Grande's concert.

Hundreds of people in Manchester are continuing to offer spare beds and rooms for those stranded in the city, using the hashtag #RoomForManchester

Image source, Twitter

Royal Oldham Hospital has told BBC Radio Manchester that it is in lockdown "due to the Manchester incident".

BBC Radio 5 live

BBC reporter Tim Ashburner told BBC 5 live he has been told by police that they have found a second suspect device and want to carry out a controlled explosion.

I'm near the Printworks in central Manchester - about 200m away from the Arena.

"The police cordon has just got a lot bigger - officers obviously want us a lot further back but they are not saying anything.

"The whole area is a lot quieter now. You can still hear the helicopter in the sky above us."

BBC reporter Tim Ashburner, who is at the scene, spoke to some volunteer paramedics who treated the injured for "shrapnel-like injuries".

Gary Walker from Leeds and his wife were just metres from the explosion, waiting for their daughters to come out.

He told BBC 5 live: "We heard the last song go and then suddenly there was a massive flash and then a bang and smoke. I felt a pain in my foot and my leg.

"I turned around to my wife who was standing at the side of me and she said, 'I need to lay down.' She’s got a stomach wound and possible a broken leg.

"I’ve got a bit of a hole in my foot where I’ve got a bit of shrapnel. I was surprised I got away so lightly."

He said he saw metal nuts that could have come from the device, and that people were using tables as stretchers.

Anne-Marie was at the concert with her 13-year-old daughter. She told BBC 5 live everybody "went into absolute panic".

"You just felt this utter shud of the building and... there seemed to be a smog at the top of the stadium and around you.

"People were dropping to the floor and thought there might be a gunman in there. Unfortunately the security were at a loss as much as anybody else and it was just each to their own.

"There were a hell of a lot of children in the building unaccompanied tonight.

"I was trying to offer my support to a number of girls who were there on their own who were hysterical. They were around my daughter’s age if not younger."

Rachel from Barnsley told BBC Radio Manchester she was in Block 213 of Manchester Arena.

She was with her 14-year-old daughter. To avoid the usual delays exiting the arena at the end of a show they decided to make their way out just before the end.

"As we were going out we heard an almighty bang. At first I thought we'd missed something in the concert.

"As we turned around the corner there was an horrific stampede of people coming down the steps, people falling on floor.

"I grabbed my daughter and we just ran.

"There were people being crushed on the floor."

Emergency services arrive at the scene of the Manchester Arena "blast".

Image source, AFP

Image source, PA

College student Sebastian Diaz, 19, of Newcastle, echoed other witnesses' descriptions of mass panic at the end of the concert.

"Ariana Grande had just finished her last song and there was a huge bang. I just saw running and it was just instinct to run," he said.

"We actually ended up in a corridor and it was a dead end. It was terrifying.

"I found the main doors and people were crying everywhere. Back at the hotel people were crying and on their phones."

Daniel Sandford
Home Affairs Correspondent

The North West Counter Terrorism Unit is treating the incident in Manchester as a possible terrorist incident, sources said.

Senior national Counter-Terrorism officers are assembling in London and are liaising with the Home Office.

Early estimates put the number of fatalities in double figures, but these are very early stages.

Calvin Welsford, 18, of Bristol: "I was in the front row and it seemed to happen at the very back of the arena.

"It almost sounded like a gunshot. That's how I would describe it. It was very loud.

"I looked around and people were just spilling down, heading out of the building.

"I was actually having an asthma attack. It was sheer panic. Security told us we needed to leave but they were very caring. People were crying."

A witness says he saw "about 30" people scattered at Manchester Arena, some who "looked dead".