LONDON: All political parties in the UK today suspended campaigning for the June 8 general election following a suicide bomb attack at a pop concert in the city of Manchester that killed 22 people and injured 59 others, including children.
British Prime Minister Theresa May has chaired an emergency response meeting of the Cabinet Office Briefing Room (Cobra) in London into the terror attack at the concert of US star Ariana Grande at Manchester Arena in northwest England.
"We are working to establish the full details of what is being treated by the police as an appalling terrorist attack," May said.
Home Secretary Amber Rudd said young people were "deliberately targeted".
Opposition Labour party leader Jeremy Corbyn said: "Today the whole country will grieve for the people who have lost their lives."
The Scottish National Party (SNP) has postponed the launch of its election manifesto, which was due today, and SNP leader Nicola Sturgeon said the news was "heartbreaking" and her thoughts were with the victims of the "barbaric" attack.
The Liberal Democrats, Green Party, Welsh Plaid Cymru and far-right UKIP have also announced that they will be ceasing campaigning until further notice.
Liberal Democrats leader Tim Farron, who has cancelled a planned visit to Gibraltar, said: "This is an attack on innocent people and the nation is united both in its grief and its determination to stand up to this deplorable attack."
The British flag have been lowered to half-mast in Downing Street as a mark of respect.
Greater Manchester Police said the explosion is being "treated as a terrorist incident until we have further information".
The attack was carried out by a man, who is believed to have walked towards the venue as the concert was concluding to detonate his suicide vest.
Eyewitnesses described seeing flying nuts and bolts and hearing a loud bang before people were thrown off.
Relatives are using social media channels to try and hunt for those still missing in the aftermath of the blast.
The injured are being treated at six hospitals around the city.
Mayor for Greater Manchester Andy Burnham said: "This was an evil act. Our first thoughts are with the families of those killed and injured and we will do whatever we can to support them.
"We are grieving today but we are strong. Today it will be business as usual as far as possible in our great city."
London's Pakistani-origin mayor Sadiq Khan said Scotland Yard was reviewing its own security in the wake of the attack.
"Londoners will see more police on our streets today. Manchester and the rest of Britain will never be cowed by terrorism. Those who want to destroy our way of life and divide us will never succeed," he said.
The attack in Manchester is the deadliest attack in the UK since the July 7 bombings across London's transport network in 2005, which claimed 56 lives.
It follows heightened security across Britain after Khalid Masood drove a high-speed car into the walls of the UK Parliament in March this year, killing four people.