Terror in UK: Explosion in Manchester leaves mass fatalities

Several people have been killed and countless others injured after a massive explosion occurred Monday night at Manchester Arena in England.

The explosion occurred as the venue was hosting a concert for the American performer Ariana Grande.

Greater Manchester Police confirmed on social media that there are “a number of confirmed fatalities and injuries.” The first blasts reportedly occurred around 10:40 p.m. local time.

— G M Police (@gmpolice) May 22, 2017

Law enforcement officials tell NBC News that at least 20 have been killed and hundreds more injured.

"We were making our way out and when we were right by the door there was a massive explosion and everybody was screaming," a witness told Reuters. "It was a huge explosion - you could feel it in your chest. It was chaotic. Everybody was running and screaming and just trying to get out of the area."

— NBC News (@NBCNews) May 22, 2017

Local reports indicate that there is a massive police presence on the scene, including squad cars, helicopters, armored trucks, and specialized bomb disposal units.

— Chris Slater (@chrisslaterMEN) May 22, 2017

There are no reports circulating about potential suspects or culprits, but authorities are now treating it as a possible terror incident and/or a suicide bombing. Reports out of Britain claim that health officials believe the victims’ wounds resulted from a possible nail bomb attack.

The North West Counter Terrorism Unit is treating the incident at #ManchesterArena as a possible terrorist incident.

— Daniel Sandford (@BBCDanielS) May 22, 2017

BREAKING: US officials briefed on Manchester explosion say UK authorities investigating arena incident as possible suicide bombing.

— NBC Nightly News (@NBCNightlyNews) May 23, 2017

Manchester Arena is the largest indoor arena in Europe, according to Reuters. The venue holds up to 21,000 people.

This is a breaking news story. It will be updated as needed.

Editor's note: The photo at the top of this piece has been replaced with a current image from the Associated Press.