Labour leader Jeremy Corbyn said his thoughts were with all those affected by the “terrible incident” in Manchester following a reported explosion at a packed concert.

His political rival Tim Farron, the Liberal Democrat leader, condemned the “shocking and horrific” attack targeting youngsters at the Ariana Grande concert.

In a message on Twitter Mr Corbyn said: “Terrible incident in Manchester. My thoughts are with all those affected and our brilliant emergency services.”

Mr Farron said: “This is a shocking and horrific attack targeting children and young people who were simply enjoying a concert.

“My deepest sympathies are with the victims, and with families who have lost loved ones, as well as those desperately waiting for news.

“I would like to pay tribute to the bravery and dedication of the emergency services.

“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.”

Liverpool’s metro mayor Steve Rotheram, whose daughters were at the Manchester Arena concert, said: “Feel sick to think that people have lost their lives at a gig attended by so many young people.

“All my thoughts go out to those parents waiting to hear of the safety of their children. It’s a parents worse nightmare. So, so sad.”

Mr Rotheram thanked the taxi driver who picked up his two girls from the venue.

Labour’s Lucy Powell, who is hoping to retain the Manchester Central seat, said she had spoken to Greater Manchester mayor Andy Burnham about the incident.

“This is a major incident targeted at our city,” she said. “Our hearts go out to all and our gratitude to emergency services.”