LONDON, May 23 (Xinhua) -- A total of 22 people, including children, were killed and 59 others injured in a suicide terror attack at Manchester Arena Monday night, police announced on Tuesday.

"We have been treating this as a terrorist incident and we believe that the attack last night was conducted by one man. The priority is to establish whether he was acting alone or as part of a network," Greater Manchester Police said in a statement.

Chief Constable of Greater Manchester Police Ian Hopkins 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."

Those injured are being treated at eight hospitals across Greater Manchester, the statement said.

Manchester police confirmed that the blast was reported to them at 22:33 summer time (2133 GMT) at the end of a pop concert by U.S. singer Ariana Grande.

"This has been the most horrific incident we have had to face in Greater Manchester and one that we all hoped we would never see," the statement said.

More than 400 officers are deployed to deal with the terrorist attack, it added.