A nine-year-old girl was fatally shot as she stood behind her mother who was trying to stop a gunman entering the family home.

Olivia Pratt-Korbel died after the shooting on Monday night when a 35-year-old man, unknown to the family, ran into the terraced house in Kingsheath Avenue, in the Dovecot area of Liverpool, in an attempt to get away from a shooter, Merseyside Police said.

Her mother Cheryl Korbel, 46, was shot in the wrist as she tried to close the door on the gunman while her nine-year-old daughter stood behind her.

The man who had entered their home suffered gunshot wounds to his upper body and, as Olivia lay dying, was picked up and taken to hospital by friends driving a dark-coloured Audi.

Speaking at a press conference on Tuesday, Merseyside Police Chief Constable Serena Kennedy said: “We will not rest until those who are responsible are put behind bars. I can guarantee that no stone will be left unturned.”

Prime Minister Boris Johnson described the shooting as an “unimaginable tragedy” and promised that Merseyside Police would get “whatever they need to catch those responsible”.

He said: “My thoughts are with Olivia Pratt-Korbel’s family and the people of Liverpool following this horrific, senseless shooting.”

The headteacher of Olivia’s school, St Margaret Mary’s Catholic Junior School in Huyton, paid tribute to the nine-year old.

Rebecca Wilkinson said: “Olivia was a much-loved member of our school. She had a beautiful smile, a lovely sense of humour and a bubbly personality.

“She was kind-hearted and would go out of her way to help others.”

The incident happened exactly 15 years after 11-year-old Rhys Jones was fatally shot in Croxteth, Liverpool.

Detective Chief Superintendent Mark Kameen said Olivia had been at home with her two older siblings and mother when Ms Korbel opened the door after hearing gunshots fired outside.

He said a figure, wearing a black padded jacket, a black balaclava with a peak, dark trousers and black gloves, fired shots at two men walking along Kingsheath Avenue, causing both of them to run away.

One of the men ran towards the open door of Olivia’s home and forced his way in, Mr Kameen said.

“As that was taking place the person with the gun has followed the male to this property,” he said.

“That person has also tried to force entry to the property and has managed, it would appear, to put their hand through the open door as Cheryl continued to try and close it.

“A shot has been fired which we believe has hit Cheryl, injuring her and then fatally wounding Olivia. Olivia at that time, we believe, was stood directly behind Cheryl.”

Olivia was taken to Alder Hey Children’s Hospital by officers but later died.

The Audi used to transport the injured man has since been seized, police said.

Mr Kameen urged the person responsible to come forward.

He said: “My appeal is to the person responsible for this horrendous attack on a nine-year-old schoolgirl to recognise the pain and anguish that this has caused to her family.

“I want that individual to hand themselves in.”

Ms Kennedy added: “This is a shocking and appalling attack which will reverberate around our communities, and I want to take this opportunity again to appeal to anybody who knows who was responsible for this attack to please come forward and give us those names.

“We need to find all who are responsible for this – not just the gunman, we need to find who supplied the weapon and who arranged this terrible incident.”

The force also appealed to the “criminal fraternity” in Liverpool for information, adding that the incident “crosses every single boundary”.