Election campaigning has been suspended in the wake of last night's suspected terror attack at the Manchester Arena, leaving 22 dead and more than 50 people injured.
Prime Minister Theresa May said: "We are working to establish the full details of what is being treated by the police as an appalling terrorist attack.
"All our thoughts are with the victims and the families of those who have been affected."
All national campaigning in the General Election has been suspended, and May plans to chair a meeting of the government's emergency Cobra committee at 9am later this morning.
An explosion happened following an Ariana Grande concert at Manchester Arena, with Greater Manchester police called to the scene just after 10.30pm, with surrounding roads closed. Greater Manchester Police chief constable Ian Hopkins confirmed the police were treating it as a terrorist incident until they had further information.
Hopkins has asked the public to report suspicious activity to the force's anti-terror hotline - 0800 789 321.
Labour leader Jeremy Corbyn has put out his full statement, saying:
I have spoken with the Prime Minister and we have agreed that all national campaigning in the General Election will be suspended until further notice.
I am horrified by the horrendous events in Manchester. My thoughts are with families and friends of those who have died and been injured. pic.twitter.com/QoCXH8qPYW— Jeremy Corbyn (@jeremycorbyn) May 23, 2017
Liberal Democrat leader Tim Farron has also cancelled a plan visit to Gibraltar after the attack.
He said: "My deepest sympathies are with the victims, and with families who have lost loved ones, as well as those desperately waiting for news.
"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."
My deepest condolences to the victims and families in Manchester. As always our emergency services have shown great bravery and heroism.— Tim Farron (@timfarron) May 22, 2017
The SNP has also postponed the launch of its manifesto, which was due to be unveiled today.