A nine-year-old girl injured when a bus smashed into a supermarket, killing a pensioner and young boy, is in a life-threatening condition.
West Midlands Police said a pedestrian aged in her seventies and an eight-year-old boy both died at the scene of the crash in Coventry city centre.
A police spokesman confirmed that the nine-year-old victim, who was travelling on the upper deck of the bus, is in a critical but stable condition in hospital.
A further casualty also remains in hospital as police investigate claims that the double-decker collided with a number of stationary cars before coming to rest.
Witnesses said the bus was travelling at high speed when it struck the frontage of a Sainsbury's store in Trinity Street, having mounted a pavement and struck a lamppost in nearby Hales Street.
A taxi driver, who did not wish to be identified, expressed shock that the double-decker appeared to have accelerated after "clipping" the rear of another vehicle on a one-way street.
The driver, who was sitting in his cab at a rank on Hales Street, said: "It just caught the corner of another bus and then it lost control.
"It just missed me by one or two metres and after that it was absolute chaos, a terrifying scene. It came like a bullet."
After the impact, near a busy pedestrian crossing close to Coventry's Transport Museum, witnesses attempted to offer what help they could and alerted the emergency services.
Maneer Fiaz, who was inside a nearby shop when he heard the crash at about 6pm on Saturday, told Sky News: "People were trying to get the driver out.
"The kids were trapped underneath the seats upstairs. It was absolute chaos. The only thing on people's minds was the two kids stuck on the top."
The eight-year-old boy who died was from Leamington, police have said, while the pensioner who lost her life lived in Nuneaton.
Superintendent Paul Keasey, head of the Central Motorway Police Group, said: "Our thoughts are with those affected by this tragic event.
"We have specially trained officers with the families at this difficult time.
"We hope to carry out a swift investigation and I would like to thank people who have already come forward who witnessed the collision.
"This is a busy area of Coventry city centre and we hope to keep disruption to a minimum as our investigation continues. No one has been arrested at this stage."
Police have yet to release details of the other casualty who is still being treated in hospital. The bus driver is understood to have suffered minor injuries.
A spokeswoman for Stagecoach Midlands confirmed one of its services travelling from Coventry to Leamington was the bus involved in the crash.