The death toll from Monday’s terror attack at a pop concert in Manchester, northern England, has risen to 22, police confirmed on Tuesday.
Fifty-nine people were injured and are being treated across eight hospitals in the Greater Manchester region.
Police said the blast was the work on one man but added their “fast-moving investigation” involving 400 officers was trying to determine if he acted alone or was part of a wider plot.
The man -- who police say detonated an improvised explosive device -- died at the scene.
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.
"We are working to establish full details of what is being treated by police as an appalling terrorist attack,” Prime Minister Theresa May said in a statement early Tuesday.
"All our thoughts are with the victims and the families of those who have been affected,” she added.
Turkey also slammed the attack. Foreign Minister Mevlut Cavusoglu said: “I condemn the terrorist attack in Manchester. Sincere condolences to the British Government and … people.”
An emergency meeting of ministers and intelligence figures -- dubbed COBRA -- will convene later Tuesday.
The current terror threat level in the U.K. has been severe, which means a terror attack is highly likely.