About 19 persons have been confirmed dead with over 50 injured in a blast that occurred at Manchester Arena, police has confirmed.
The attack occurred some hours ago.
Sources said they heard two loud bangs, reported to be in the foyer, after a pop concert by American Ariana Grande at the Manchester Arena.
Also, Greater Manchester Police said there are a “number of confirmed fatalities and others injured”.
The cause of the explosion is unknown but the North West Counter Terrorism Unit is treating it as a possible terrorist incident.
According to the BBC, senior counter-terrorism officers are assembling in London and are liaising with the Home Office.
Early estimates put the number of fatalities in double figures, although these are not confirmed.
Manchester Victoria station, which is close to the concert venue, has been closed and all trains cancelled.
British Transport Police say explosion was in the foyer area of Manchester Arena.
Speaking on the explosion, a father, named Andy, said he was blown “about 30ft” by a blast that shook the building as he waited to collect his wife and daughter at the end of a concert by US artist Ariana Grande.
He said he later saw panicking families trying to find loved ones in the wake of the incident on Monday night.
He said: “It’s shocking what happened. Just carnage everywhere. There was a good 20 to 30 of them [victims]. Some were young kids, some were disabled people.”
“As I was waiting an explosion went off and it threw me through the first set of doors about 30ft to the next set of doors.
“When I got up and looked around there was about 30 people scattered everywhere, some of them looked dead, they might of been unconscious but there was a lot of fatalities.
“My first thing was to run in the stadium to try and find my wife and daughter.
“When I couldn’t find them I looked back outside and the police, fire and ambulance were there and I looked at some of the bodies trying to find my family. “Luckily they weren’t there, I managed to find them outside the arena and got them back to the hotel.”
One man 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.