They found a 45-year-old man and an 11-year-old girl; a second girl, believed to be in her early teens, was pronounced dead at the scene.
A police spokeswoman said the man and girl had suffered serious injuries. Officers believe the three are from the same family.
Police have informed the family about the crash.
A spokesman for GMP said: ‘Police discovered a man and two children in the vehicle. A 45-year-old man and an 11-year-old girl have been taken to hospital. Sadly a teenage girl was pronounced dead at the scene.’
One eyewitness told.I ran outside and saw the car crashed into the wall. I went over to the car straight away and tried to help. The male driver was stuck in the car, his knees were tucked in.
‘We then tried to help the the girl in the front seat and was able to get her out. Sadly the girl in the back seat had already died. It was just horrific.’
Police originally believed that two boys had run from the vehicle shortly after the collision. This was confirmed to be incorrect information and police are no longer searching for any other passengers.
An investigation is ongoing and police are appealing for anyone who may have seen the collision to contact police as soon as possible.