Two more men, aged 39 and 26, have been arrested in connection with a hit-and-run incident in Leeds which left a two-year-old boy and his 10-year-old sister fighting for their lives, West Midlands police have said. A 36-year-old man remains in custody.
Raham Saleem and his sister Sabam were knocked down by the car on their way to buy onions for the family's Eid celebrations.
Officers said the driver slowed down to see what had happened, then sped away from the scene.
In CCTV released on Monday, police were trying to trace a Vauxhall Astra in Brudenell Road, Hyde Park, Leeds, at around 5.20pm on Saturday.
The children underwent surgery at Leeds General Infirmary where Sabam remains in a critical condition.
But West Yorkshire Police said her brother was now improving and has been moved out of the intensive care unit.
Two-year-old Raham, who was struck by the car along with his sister, is said to be improving
Detectives said they are continuing to trawl through CCTV.
They believe a woman seen on the street at the time may well have witnessed what happened.
Mr Taylor said on Monday: "We are making progress with this investigation which is drawing on specialist resources from across the force, including homicide officers and our specialist Major Collision Enquiry Team.
"We have received a lot of support from residents who are helping us investigate a truly shocking incident in a very close knit community and are determined to leave no stone unturned to locate this driver."
On Monday, Mr Taylor said Sabam's father described Saleem as "the apple of his eye", while her brother was due to start nursery in October.
Officers have said the children had walked a couple of hundred yards from the shop when they crossed near the Makkah Masjid Mosque.
The two children went on the errand with a cousin, who escaped injury.
The road is used as a short-cut locally, but has speed bumps.
The children's aunt, Saima Rafique, told BBC Look North her niece's condition was very serious.
"We want her home," she said. "I really want my princess home.