A two-year-old boy and his 10-year-old sister were critically injured in a hit and run after they walked home after buying onions for the family's Eid celebrations.
Raham Saleem and his sister, Sabam, were knocked down by a silver Vauxhall Astra in Brudenell Road, Hyde Park, Leeds, at around 5.20pm on Saturday.
The pair had gone to the shop to buy onions for their mother for Eid celebrations, which mark the end of Ramadan, the holy month of fasting observed by Muslims.
West Yorkshire Police said the driver slowed down to see what had happened, then sped away from the scene.
The children underwent surgery at Leeds General Infirmary where they are in a critical condition.
Detective Superintendent Paul Taylor, of the homicide and major inquiry team who is leading the investigation, said: "They were crossing the road and were struck by a vehicle, both were injured and underwent operations overnight.
"We are very concerned about their condition."
Detectives know the car is a mark four model, meaning it was made between 1998 and 2005.
"I would appeal to that driver to come forward so he or she can tell us what happened," Mr Taylor said.