Following the incident in Manchester, Merseyside Police Chief Constable Andy Cooke said: "Our thoughts and sympathies are with everyone affected by the terrible events in Manchester last night.
"At least 22 people have tragically died, and 59 others have been injured during what should actually have been a safe and enjoyable night out at a concert for young people and their families.
"Our colleagues at Greater Manchester Police and British Transport Police have worked tirelessly throughout the night to investigate what happened and protect the public and we will support them in every way we can.
"The other emergency services, including the North West Ambulance Service, were in attendance at the Manchester Arena, where they provided emergency treatment to the dying and those injured during the explosion.
"A number of officers from this force have travelled to Manchester to offer mutual aid to our colleagues and other officers have come into work having been off-duty to maintain a visible presence in our own communities.
"I know that this attack will feel very close to home for many local people who will understandably be worried, especially those who may have had children and family members at the concert last night.
"I would like to take this opportunity to reassure communities across Merseyside that their safety is paramount and there is currently no specific threat to any particular locations, or areas here, but that said we must all remain vigilant.
"We regularly conduct training exercises with Merseyside Fire and Rescue Service, North West Ambulance Service, the local authorities and other partner agencies to test our response to incidents such as this. We have reviewed our resources as part of a range of measures to reassure communities and make sure we are well protected during these times of high alert.
"Police officers and staff from our partner agencies throughout the city and county will, as always, be asked to be vigilant and we will maintain a visible presence in and around key locations.
"At times like this it is vital that all communities pull together and support each other. Everybody, from law enforcement, to businesses, to the general public, has a role to play in keeping the UK safe from terrorism.
"Be vigilant. If you suspect it, report it. Nobody is better placed to detect something that is out of place in their communities than the people living in them. We would encourage you, if you do see any suspicious activity, to call the Anti-Terrorist Hotline on 0800 789 321 or call police on 999.
"An emergency number is available for those who are concerned about loved ones or anyone who may have been in the area - 0161 856 9400.
"If you have any images, or footage, from last night that you believe could assist Greater Manchester Police then upload them to Ukpoliceimageappeal.co.uk.
"Finally, I would like to add that we cannot let the terrorists disrupt our daily lives and we should continue to do what we would do normally. Already the strength, courage and humanity of some of those who found themselves caught up in the tragic events of last night is beginning to show through. We must never lose sight of the fact that there are more good people in this world than bad and the response of the people of Manchester and the North West following this tragedy speaks volumes."