Police say an explosion at an Ariana Grande concert in northern England has killed at least 19 people and injured about 50, the AP reports. Billboard has confirmed that the American singer herself is OK. Police suspect a suicide bomber set off the blast, which is being treated as a terrorist attack unless new information emerges, NBC News reports. A statement from Manchester Arena said the explosion took place outside the arena just after the concert, as people were exiting. "A huge bomb-like bang went off that hugely panicked everyone and we were all trying to flee the arena," concertgoer Majid Khan, 22, tells Britain's Press Association. "It was one bang and essentially everyone from the other side of the arena where the bang was heard from suddenly came running towards us as they were trying to exit."
Video from inside the arena showed concertgoers screaming as they made their way out amid a sea of pink balloons. Authorities say most of those being taken to the hospital had shrapnel injuries. "Praying for everyone at Ariana Grande's show," tweeted Katy Perry, one of the many celebs taking to Twitter to voice support, per CBS News. Britain's terrorist threat level has been set at "severe" in recent years, indicating an attack is highly likely. Reuters reports Manchester Arena is the biggest indoor arena in all of Europe, and can hold 21,000. The concert was part of the 23-year-old Grande's Dangerous Woman Tour. After Manchester, Grande was to perform at venues in Belgium, Poland, Germany, Switzerland, and France, with concerts in Latin America and Asia to follow. (Read more explosion stories.)