An eight-year-old girl was hit by a car in Monton.
Paramedics fought in vain to save the child at the scene.
The collision occurred at the intersection of Monton Road and Cavendish Road.
A man was arrested on suspicion of death by dangerous driving.
In a statement, Greater Manchester police said: "Just before 10:40 am, police were called to report a collision between a blue Vauxhall Corsa and a pedestrian mall in Monton Road, Monton.
"The pedestrian – an eight-year-old girl – was treated by paramedics, but unfortunately was declared dead at the scene.
"A 24-year-old man was arrested for suspecting that he was killed by dangerous driving and remains in detention for interrogation.
"The Monton Road is currently closed between the Cavendish Road and the Half Edge Lane.
GMPs Serious Collision Investigation Unit police officer Lee Westhead said, "A tragic child has lost his life this morning and we're doing everything we can to support your family during this devastating time.
"I would ask anyone who has witnessed the collision, or anyone with information, to contact my team on 0161 856 4741."
"Road closures will be maintained during the afternoon as investigations are being conducted. Avoid avoiding the area as much as possible.
Anyone with information should contact GMP's Serious Collision Investigation Department at 0161 856 4741, reference number 09/11/2018, or the independent Crimestoppers Charity anonymously at 0800 555 111.