Police said 19 people were killed and approximately 50 others were injured after reports of an explosion at Manchester Arena in the U.K. on Monday night, where Ariana Grande was performing a concert, WHO confirms.
The explosion was reported “within the foyer area” of the venue about 10:30 p.m., according to the British Transport Police. A tweet from Manchester Arena said the explosion took place “outside the venue in a public space.”
The cause of the explosion was unclear, but Manchester police said on Twitter that “this is currently being treated as a terrorist incident until police know otherwise.”
Local investigators and arena authorities could not immediately be reached for further comment.
It was also unclear if the concert had concluded at the time of the explosion. But an eyewitness, Josh Elliot, told the BBC that it was heard just as Grande finished her final song of the night.
“Ariana is okay,” her rep said in a statement to WHO. “We are further investigating what happened.”
Eyewitness Andy Holy spoke to the BBC and said he was blown through a door at the arena. “It was definitely an explosion and definitely a lot of fatalities,” he said.
“My ears are still ringing,” he said. “The whole building shook.”
Esme Findlay was inside the arena at the time and tells PEOPLE, “Everyone was laughing and talking about the show before the sound. [Then] everyone began screaming immediately and pushing to get out.”
“It was very loud afterwards because of the screaming,” she says. “No one knew if it was a bomb or what it was, but people were screaming ‘bomb, bomb,’ and there was a lot of panic.”
“Outside, people were screaming names of people,” says Findlay, 20. “I think they were people who they had been with and couldn’t find.
“Everyone was looking for someone. I saw some girls crying and a woman was asking them where their parents were. It was the scariest thing I’ve ever seen in my life.”
Holy, who said he was there with his wife and daughter, told the BBC he saw at least 30 casualties, including many children.
Many of those hurt or killed appeared to be waiting outside the arena to meet their kids, said Holy, who is safe with his family at their hotel.
Sam Coley lives about half a mile from the arena and tells PEOPLE even he could hear the sounds of a “massive bang.”
“There was an unbelievable amount of police cars and ambulances and people on the street,” says Coley, 24. “Around 50 police vehicles must have gone past my flat, if not more. Then the ambulances started coming in a convoy.”
“It was a loud bang,” he says, “Loud enough to hear over the TV inside my flat — and I’ve got pretty thick doors and double glazing.”
One video shared on Twitter appeared to show the inside of the arena in the aftermath of the incident, with people screaming and streaming to the exits.
Social media users soon began circulating the hashtag #RoomForManchester to alert stranded people to places where they could stay for the night.
Holiday Inn reported taking in more than 50 youths, some of whom were waiting to be reunited with parents and guardians.
This is a breaking news story. Please return for updates.
This article originally appeared on PEOPLE