British police said 22 people including some children were killed in a suicide attack carried out by one man after a concert in Manchester on Monday.
“We believe, at this stage, the attack last night was conducted by one man,” Manchester Chief Constable Ian Hopkins said Tuesday morning.
“The priority is to establish whether he was acting alone or as part of a network.
“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.”
This is the deadliest terror assault in Britain since four British Muslims killed 52 people in suicide bombings on London’s transport system in July 2005.
Police said the terrorist died after detonating explosives shortly after 10:33 p.m. local time.
Prime Minister Theresa May, who faces an election in two-and-a-half weeks, said her thoughts were with the victims and their families. She and Jeremy Corbyn, the leader of the opposition Labour Party, agreed to suspend campaigning ahead of the June 8 election.
“We are working to establish the full details of what is being treated by the police as an appalling terrorist attack,” May said in a statement. “All our thoughts are with the victims and the families of those who have been affected.”
May is due to hold a crisis response meeting.
There was no immediate claim of responsibility, but U.S. officials drew parallels to the coordinated attacks in November 2015 by Islamist terrorists on a concert hall and other sites in Paris, which claimed about 130 lives.
Islamic State supporters took to social media to celebrate the blast and some encouraged similar attacks elsewhere.
Britain is on its second-highest alert level of “severe,” meaning another attack by terrorists is considered highly likely.
British counterterrorism police have said they are making on average an arrest every day in connection with suspected terrorism.
In March, a British-born convert to Islam plowed a car into pedestrians on London’s Westminster Bridge, killing four people before stabbing to death a police officer who was on the grounds of Parliament. The man was shot dead at the scene.
In 2015 Pakistani student Abid Naseer was convicted in a U.S. court of conspiring with al-Qaida to blow up the Arndale shopping center in the center of Manchester in April 2009.