A suspected terrorist attack in Machester Arena in Manchester, England while an Ariana Grande concert took place left 22 dead and 59 injured Monday night.

The suspected lone attacker died at the scene after placing and detonating the explosives. Among the victims are an 8-year-old girl and twelve children under the age of 16 who were seriously injured.

The explosion took place in the arena’s foyer as guests exited the concert.

“We struggle to comprehend the warped and twisted mind that sees a room packed with young children not as a scene to cherish but as an opportunity for carnage,” Prime Minister Theresa May said Tuesday.

Isis claims responsibility for the attack, stating that a “soldier of the caliphate” placed explosives at a gathering of “crusaders” – meaning Christians – at Machester Arena, ABC News reported.

The threat level remains severe in the United Kingdom, indicating that another attack may be likely. Greater Manchester Police arrested a 23-year-old man in South Manchester in connection with Monday night’s attack, ABC News reported.

A controlled explosion took place in Fallowfield, a suburb of Machester, where a warrant has been executed as part of an investigation.