Monday 22's attack outside an Ariana Grande concert at Manchester Arena killed at least 22 people, including children, and was carried out by a lone suspect carrying a bomb, Manchester Police said.
"The attacker, I can confirm, died at the arena. We believe the attacker was carrying an improvised explosive device, which he detonated, causing this atrocity," said Chief Constable Ian Hopkins.
While police believe the suspect was acting alone, investigations are ongoing to establish if he was part of a network.
As many as 400 police were deployed overnight, Hopkins said early Tuesday. He added that residents should expect to see more armed officers on the streets.
Social media posts from the scene showed panicked concertgoers running down the arena's stairs in an attempt to get away.
- Lucía Forero and María García