The child, who has not been named, was hit by the vehicle at Hillside Road in Portlethen, near Aberdeen, at around 4pm yesterday.
It was reported locally the resident was driving the car when it struck the youngster in the commuter suburb.
Grampian Police, which has launched an investigation, was unable to comment on the reports.
One resident posted online: "Awful news. It was the little girl's neighbour, my heart goes out to both families."
Another added: "I don't know how any of them will be able to come back from this, it is so heartbreaking."
Emergency services were called to the street and the youngster was rushed to Aberdeen Royal Infirmary, but police confirmed she died a short while later after suffering fatal injuries.
Inspector Ian Kirkwood, of Grampian Police, said: "Tragically, a young girl has lost her life as a result of the incident.
"Her parents have been informed and our thoughts are with them at this extremely difficult time.
"It is too early to speculate on the cause of the collision and I would appeal to anyone who witnessed the incident or its immediate aftermath, and who has not yet spoken with police, to contact us as soon as possible."
The local community was last night in shock over the tragedy.
One local resident whose house backs onto the scene said he had been at work during the accident.
The man, who did not want to be named, said: "We didn't see anything until we came in from work about 6pm.
"We heard it was a little girl that had died.
"There's usually lots of kids running about with the park nearby – it's pretty tragic."
Many people also posted messages of condolence to the family online.
Stacy Smith wrote on Facebook: "Thoughts go out to the family and friends of the little girl who was ran over and sadly passed away earlier today in Portlethen.
"Can't begin to imagine what her parents are going through.
Emma Trotter posted: "Thoughts go out to the family of the little girl who was hit by a car earlier today.
"It's such a terrible thing for any parent to have to go through."
Police conducted door-to-door interviews late into the evening in a bid to establish what exactly happened.
The road remained closed last night as officers examined the scene, and local diversions were in place.
Anyone with information on the accident is asked to contact Grampian Police on 101.
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