Two children died and their mother was left with serious injuries after a car ploughed into a group of five pedestrians while they were apparently on their way to the park.
West Midlands Police said the girls, aged six and seven, were taken to hospital after the incident in Handsworth, Birmingham, around noon yesterday "but despite the best efforts of medical staff died shortly afterwards".
The girls' mother is believed to be among those seriously injured in hospital. The family are believed to be of Chinese origin, according to eyewitnesses.
A 34-year-old local man has been arrested on suspicion of dangerous driving.
City councillor Waseem Zaffar, who visited the scene of the crash today, said: "I have been in the area this morning listening to the community and what they have to say about the road.
"I have been told the mother is among those seriously injured.
"Everyone is in total shock. It was a lovely, sunny Sunday afternoon and the family were apparently on their way to the park, which is just a few minutes away.
"We will be calling for a meeting with the transport department (on Birmingham City Council) to see what can be done to prevent any more lives being lost."
In total, four children and a woman were involved in the incident. They were reportedly crossing the road in front of a parked bus in Grove Lane when they were hit by the car.
Police said a 12-year-old girl and a 13-year-old boy were being treated for serious injuries which are not believed to be life threatening. A 39-year-old woman remains in a critical condition.
Sergeant Steve Newbury, from the force's collision investigation unit, said: "We still continue to investigate the circumstances around this tragic incident and officers continue to liaise with the family of those involved.
"I am appealing for witnesses to come forward, in particular I want passengers who were travelling on the number 101 bus at around noon along Grove Lane towards Oxhill road to call me or one of my team."
Anyone with information is urged to call the collision investigation unit on 101.
Birmingham City Council member Gurdial Singh Atwal, who has lived in the Handsworth area for nearly half a century, said the road has been the scene of several accidents in recent years.
He said: "I know every inch of Grove Lane and there have been problems here with traffic.
"Somebody was killed here only recently (before yesterday's crash).
"The roads seem very narrow these days with cars parked on one side, which can create problems for road users and pedestrians.
"Some people want more police to monitor the area, some people say they want speed cameras, others are concerned about drivers speeding.
"We will wait to see the results of the police investigation now."