At a news conference Monday evening, Greater Manchester Police Chief Constable Ian Hopkins said authorities are treating the explosion at Manchester Arena as a "terrorist incident" until they have further information.
"This is a very concerning time for everyone," Hopkins said. =
British Transport Police said an explosion occurred in the foyer of Manchester Arena at 10:30 p.m., around the time the concert finished. Arena management tweeted its own statement, which said the incident took place "outside the venue in a public space."
Police have focused their investigation on one man whose actions suggest he was the attacker, according to a law enforcement official not authorized to discuss the investigation.
Authorities say they believe one man detonated an improvised explosive device and was killed in the explosion.
Late tonight, Grande shared a message on Twitter writing: "broken. from the bottom of my heart, i am so sorry. i don't have words"
broken. from the bottom of my heart, i am so so sorry. i don't have words.