British premier Theresa May on Tuesday said police now knew the identity of the attacker who bombed a pop concert in Manchester on Monday night, killing at least 22 people.

Axar.az reports citing Anadolu Agency, fifty-nine people were also injured when a bomb exploded at an arena in Manchester, northern England.

The attacker also died in the attack.

Daesh group on Tuesday has claimed responsibility for the deadly attack.

May, speaking after an emergency meeting of British ministers and intelligence figures, described the blast as “appalling and callous”.

“This was amongst the worst terrorist incidents witnessed in the U.K.", she added.

May said the identity of the perpetrator was known to police but the authorities would not be revealing more information for the moment.

She said many of the 59 casualties being treated across eight regional hospitals had life-threatening injuries.

Shortly after May spoke, police evacuated a major shopping center in central Manchester, amid an alert.

All campaigning ahead of the country’s June 8 general election has now been suspended.

May will travel to Manchester later on Tuesday and another emergency COBRA meeting will be held.

Police had earlier said the blast was the work of one man but added their “fast-moving investigation” involving 400 officers was trying to determine if he had acted alone or was part of a wider plot.

Monday night’s blast at the 21,000-seat Manchester Arena took place shortly before 10.35 p.m. (2135GMT) local time.

The arena had been hosting a concert by U.S. pop star Ariana Grande and thousands of children and young teenagers were among the crowd.