Sgt Brian Orr, of GMP's serious collision investigation unit, said: "This was a heartbreaking incident involving a young boy, which has understandably left his family distraught".
Armed police are said to have entered the building in Salford Quays around 30 minutes ago.
One witness to the incident said: "All I know is someone, reportedly a young child, was hit at least twice by a vehicle in the auto park".
According to the Manchester Evening News the infant was sadly killed at the scene after he was stuck twice by the vehicle believed to a Toyota Rav-4.
A young boy has died following a collision with a vehicle in a hotel auto park.
An "ongoing" police operation is being reported at the Ibis Budget Hotel in Manchester, with mass armed police presence and reports of disturbing screams and people covered in blood. I couldn't actually see anything though, just some very distressed people'.
Kenny Turton-Ainsworth wrote: "Not sure what happened but the screams were blood curdling!"
Police also told the MEN they were dealing with an "ongoing" incident.
Chilling mobile phone footage posted online also captures a woman breaking down in tears.