A number of dangerous dogs have been seized in a crackdown on owners who flouted court orders which allowed them to keep the animals.
More than half the owners in Merseyside who have been granted an exemption to keep banned breeds had breached their conditions, police said.
As a result, Merseyside Police identified 42 dogs as a danger to the public and so far have seized 15 of them as part of the operation in Wirral, Sefton, Knowsley, St Helens and Liverpool.
Since January 2007 three people have been killed in dog attacks in the force area - three-year-old Ellie Lawrenson, four-year-old John Paul Massey and Clifford Clarke, aged 79. Both of the children were killed by banned pit-bull dogs.
In a statement, Merseyside Police said: "We don't want other families to suffer the loss of a loved one, or another innocent person to lose their life, as the result of an attack by a dangerous dog.
"We want to ensure responsible dog ownership across Merseyside, particularly in relation to dogs which have been classified as dangerous and are exempted under the Dangerous Dogs legislation.
"Despite the deaths of three people, and the devastating impact it has had on the victim s' families, there are still people within our communities who still see fit to breed these dangerous dogs despite the threat they pose and the fact that they are illegal breeds."
Chief Inspector Chris Gibson said: "We want to be clear that we don't want to demonise all dogs, or their owners.
"The action taken across Merseyside today is solely in relation to banned breeds which have been given exemptions by the courts. When the courts grant these exemptions there are nine conditions imposed by the courts, which the owner must abide by.
"On Merseyside there are 247 owners of dogs who are exempted under Dangerous Dogs legislation; of these 130 are in breach of their conditions.
"The owners of the dogs seized by officers today were issued with a Contingent Destruction Order by the courts and the dog was then placed on the Dangerous Dogs Index and the owners were sent a letter by Defra (Department for the Environment, Food and Rural Affairs) advising them of the terms and conditions that were in place and that their dog may be destroyed if they breached the conditions.
"Defra monitors whether the owners have maintained the insurance required and remind owners when the insurance is due to expire. And if they fail to renew the insurance the relevant police force is advised and appropriate enforcement action can then be taken.
"Where the owners have failed to adhere to the conditions following exemption by the courts and have ignored the advice of the notice from Defra we have carried out further research to identify which of these 130 dogs are a danger to the community.
"This research identified if dogs were linked to organised crime groups, or if there were children or vulnerable adults in the property where the dogs were being kept.
"As a result of the failure to adhere to the exemption conditions of the court and other aggravating factors, we identified and prioritised 42 of those dogs as a danger to the public and have taken the required action this morning. So far 15 dogs have been seized as part of the operation.
"The dogs seized by officers today will be humanely destroyed. One of the dogs seized this morning belongs to a 23-year-old man who is currently awaiting trial for being concerned in the supply of a Class A drug.
"Let's be clear - these dogs pose a danger to the public as well as to the families where they are housed. Invariably the people who keep these dogs, keep them as a status symbol and are not responsible dog owners.
"I'm sure that if you were to ask members of the public there aren't many who would be happy living next door to someone who owns one of these dogs and does not take their responsibilities seriously, and I'm sure there aren't many who would be happy to let their children, or grandchildren play out in the street if one of these dogs was in the vicinity.
"These dogs are fighting dogs, they are not designed to be family pets.
"Where owners have made applications to the court and have been granted an exemption it is up to that dog owner to adhere to the conditions and prove responsible dog ownership.
"If those owners are not prepared to abide by the conditions imposed, we have no alternative but to take the action we have undertaken today to keep our communities safe."
Anyone with information on where illegal dogs are being bred, who is supplying them or who is using these animals as part of their criminal lifestyles, should call police on 101, or contact Crimestoppers anonymously on 0800 555 111.