Lexi Branson was mauled at a flat in Rowena Court in Mountsorrel, Leicestershire, yesterday, police said today.
Leicestershire Police said they are investigating the circumstances surrounding the death of the girl.
Police confirmed that Lexi had been attacked by a dog in what is believed to be the lounge area of the home address.
"Lexi was taken to the Queen's Medical Centre in Nottingham where she subsequently died." police said in a statement.
Detective Superintendent David Sandall, overseeing the investigation, said: "This is a very tragic incident and our thoughts are with the family and friends of Lexi at this extremely difficult time."
"The flat remains cordoned off to allow for a forensic examination and we are continuing to investigate the circumstances leading to the tragic death of Lexi and this will include the history of the dog.
"The dog is a bulldog which is not a breed listed under Section 1 of the Dangerous Dogs Act," Sandall said.
"Lexi was a bubbly, bright little girl. She fought for her life from the moment she was born as she was born three months prematurely. She's been taken from us so tragically.
"She will be sadly missed, she will be our shining star in the sky and she we will never be forgotten," they said.
Late last month, the British government said owners of dogs that attack and kill people will face 14 years in jail.
According to the proposed rules, if a dog injures someone in an attack its owner could be imprisoned for five years, and if a guide dog is attacked the penalty would be three years in jail.
The government had launched consultation months after a 14-year-old girl was savaged to death by four dogs while visiting the home of a friend in Greater Manchester in March.
The dog's owner, Beverley Concannon, was given a 16-week jail sentence, suspended for 12 months. She was also banned from keeping dogs indefinitely.