A woman and a toddler have been taken to hospital after being hit by a car.
Ambulance services were called to Larkshall Road, opposite Tesco in Highams Park, at 11am following reports of a collision.
Two women, one pushing a three-year-old boy in a pram, were using a pedestrian crossing near the Tesco superstore, when the women with the pram was hit by a Renault Scenic.
The woman, 25, suffered lacerations to her head, which police have described as "very serious" and was taken to Royal London Hospital.
The boy, which was thrown from the pram, was taken to Whipps Cross Hospital with what are described as minor injuries.
The driver of the Renault, a man in his 80s, has not been arrested but is said to be assiting police.
Eyewitness Barry Gittos was standing opposite the crossing when the collision happened.
He said: "I heard a massive thud and saw the lady on the floor near the pavement and a woman standing next to her screaming.
"The baby was strapped to a car seat and had been seperated from the pram, which must have happened when the car collided.
"Lots of people ran over and I called the police."
Mr Gittos believes the Renault must have been travelling at some speed as the car stopped 2 to 3 metres past where the mother had been hit.
The toddler was seen strapped to the seat in the road.
A total of five police cars and seven officers remain at the scene.
Detective Sergeant Lambert said: "We’re investigating a very serious personal injury collision."
Larkshall Road is closed around the junction with The Broadway