Some 59 people were also injured when the blast caused by an improvised explosive device carried by the attacker detonated at the Manchester Arena.
Announcing that the death toll had risen, Greater Manchester Police chief constable Ian Hopkins said: ‘What I can confirm is that there are children among the deceased.’
West Yorkshire Police Chief Constable Dee Collins said: “In such a tragic and terrible time the thoughts of everyone connected with the Force are with all those who lost their life or were injured during the explosion and for the family members and friends who lost a loved one.
“We stand shoulder to shoulder with the people of Manchester and our colleagues in Greater Manchester Police and we have provided practical support to the Force.
Emergency numbers have been established for anyone who is concerned for loved ones who may not have returned home 0161 856 9400 or 0161 856 9900.
“The public’s safety remains our top priority and we have already increased patrols of highly visible officers across West Yorkshire. This includes an increase in armed officers at key locations including transport hubs.
“This is a concerning time and I hope that our increased presence helps to reassure the public that we are working with our partners to do everything we can to protect the security of the communities we serve.
“Likewise I would urge our communities to come together and show our strength in unity.
In a joint statement Bradford Council Leader Coun Susan Hinchcliffe, the Lord Mayor of Bradford, Coun Abid Hussain, and Bradford Council Chief Executive, Kersten England, said: “Our thoughts and prayers are with all those affected by last night’s terrible incident at Manchester Arena, which is believed to be a terrorist attack. We are aware that a number of people from our district are among the injured and we wish them a swift and full recovery.
“The Union Flag on City Hall has been lowered as a mark of respect, in line with all government buildings across the country.
“The Council will continue to plan and work with all its partners, including West Yorkshire Police, to ensure that the Bradford district remains safe and vigilant in the face of any threat of terrorism.”
Sir Richard Leese, leader of Manchester City Council, said: ‘This is an absolutely horrifying incident and our thoughts are with everyone affected, especially those who have lost loved ones or been injured and traumatised.
‘If it is confirmed this was a terrorist attack it is a monstrous act but also a deeply futile one.
‘Manchester is a proud and strong city and we will not allow those who seek to sow fear and division to achieve their aims.’