A suicide bomb blast in the city of Manchester, England, killed at least 22 people and injured more than 50.
The explosion occurred on Monday night at Manchester Arena after a performance by US pop singer Ariana Grande.
A suicide bomber attacked the indoor arena as concert-goers, including children and teens, were leaving the concert.
The blast is believed to be a terror attack by the Greater Manchester Police, according to media sources.
Left uninjured by the explosion, Grande tweeted, "From the bottom of my heart, I am so so sorry. I don't have words."
Manchester Chief Constable Ian Hopkins was quoted by Reuters as saying: "We believe, at this stage, 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.
"The attacker... died at the arena. We believe the attacker was carrying an improvised explosive device which he detonated causing this atrocity."
The US Department of Homeland Security (DHS) said late Monday that they have ‘no information to indicate a specific credible threat involving music venues in the US’.
However, the public may experience ‘increased security in and around public places and events as officials take additional precautions’, DHS stated.