Panicked families have turned to social media in a desperate attempt to locate their loved ones after 19 people were killed and 50 injured when explosions went off at Manchester Arena.
Video footage showed thousands of people fleeing in tears from the venue, many covered in blood, after the Ariana Grande concert finished on Tuesday night.
There were reports online that more than 50 children that left the stadium without guardians have been taken to the nearby Holiday Inn.
Thousands of social media users started using the hashtag #ManchesterMissing to circulate images of hundreds of missing concert-goers in a bid to track them down.
Manchester Police have set up an emergency number - 0161 856 9400 - for those who are concerned about loved ones or anyone who may have been in the area.
Facebook has also activated its safety check feature, which allows people close to the arena to confirm whether they are safe or not.
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MISSING: These women are reportedly missing after a friend posted their photos on Facebook saying she hadn't heard from them
Concert-goers helped injured people make their way from the gig in Manchester tonight
FOUND: 'My six-year-old niece was in Manchester tonight for the concert. We haven't heard from her/ her guardian and are sick with worry,' one woman tweeted after the explosion. The young girl has since been located.
'My six-year-old niece was in Manchester tonight for the concert. We haven't heard from her/ her guardian and are sick with worry,' one woman tweeted after the explosion.
A woman named Paula Robinson said she was looking after many of the children at the hotel and urged worried parents to get in contact.
'Please re-post for any parents with children at M.E.N. We have taken as many kids as we can to Holiday Inn. We will keep them safe and stay with them,' she wrote.
The people of Manchester are offering up their own homes for stranded concertgoers, using the hashtag #RoomForManchester across social media.
At 3am Ian Hopkins, chief constable of Greater Manchester Police, said they were treating it as a 'terrorist incident' and that the injured were being cared for at six hospitals.
According to social media posts, a small group of these missing teenagers have since been found. FOUND: Top row - third from left, Second row - fourth from left, Third row - second, third, fourth and fifth from left, Fourth row - fifth from left
A woman named Paula Robinson said she was looking after many of the children at the inn and urged worried parents to get in contact
Concert attendee Jake Wallis Simons said relatives are standing aimlessly in the streets around Manchester Arena desperate for news about their loved ones.
Andrew Senior, 41, told MailOnline: 'My wife and two daughters were in there. They were wounded by shrapnel but they are OK.
'I spoke to them on the phone. All the casualties are sitting on the floor outside waiting to be taken to hospital. My wife and daughters are separated but they are OK.
'I feel really worried and I just wish I was with them. It's at times like these that you realise how lucky you are.'
FOUND: Leah was reported to be safe by a friend
MISSING: Many turned to social media to share their concern for missing loved ones
Bloodied concertgoers were pictured being helped by armed police outside the arena after explosions rang out at the gig
Greater Manchester Police said they were working on getting a phone number for concerned family members to call
Armed officers surrounded the venue and bloodied casualties were seen being stretchered out of the concert that resembled a 'war zone'.
There were fears a 'nail bomb' had been used as witnesses described there being 'nuts and bolts flying everywhere.'
Last night police carried out a controlled explosion at Cathedral Gardens after finding a second suspicious device.
Jade Baynes, 18, from Hull, was told to run from the area by armed police after leaving the concert arena.
She said she heard loud bangs and what sounded like gunshots just after the entertainment had finished.
She said: 'There were just a loud bang and a flash and everyone tried to scramble out. An alarm came on telling everyone to stay calm but leave as quickly as possible.'
She added that there appeared to be some sort of commotion in the first tier of the arena, with a number of stewards stood around the seats.
A bomb disposal team from the Army's Royal Logistics Corps arrived at the scene shortly after the incident, with reports that sniffer dogs could be heard coming out of the van.
Witnesses reported hearing a 'huge bang' at the venue shortly after US singer Ariana Grande's gig finished
Concert-goers and witnesses have described the chaos after 'huge bomb-like bangs' went off in Manchester Arena following an Ariana Grande gig
Casualties are stretchered out of the concert tonight after a terror attack in the Ariana Grande concert
This was the view of the street outside Manchester Arena tonight after there were explosions at the Ariana Grande gig
Manchester's Victoria station, which backs onto the arena, has been evacuated and all trains cancelled.
Greater Manchester Police said: 'Emergency services are currently responding to reports of an explosion at Manchester Arena.
'There are a number of confirmed fatalities and others injured.
'Please AVOID the area as first responders work tirelessly at the scene. Details of a casualty bureau will follow as soon as available.'