A baby has died and three others have been seriously injured after a Toyota Kluger left the road and slammed into a tree in Perth’s southeast.

The silver SUV was travelling along Nicholson Rd in Lynwood about 3.40am on Saturday when it veered off the carriageway and struck a tree, triggering a major emergency response.

A 35‑year‑old man — a ride‑share driver — was behind the wheel and sustained minor injuries.

The passengers, a 32‑year‑old woman and a seven‑month‑old child were rushed to Fiona Stanley Hospital with serious injuries.

But the baby later died despite efforts to save them.

Her three‑year‑old daughter was taken to Perth Children’s Hospital, also with serious injuries.

Residents rushed to help during the early morning crash.Residents rushed to help during the early morning crash. Credit: 7NEWS

Witnesses have described the scene as “very horrible”, leaving the community reeling.

“She was like begging – everyone ‘my baby’s not crying please help us, please help us – my baby’s not breathing’,” one witness said.

The impact of the crash was so strong it wiped out a concrete bus stop bench before slamming into a tree.

Residents say around 10 people rushed out to help, some providing first aid.

“Before there was no breathing but after the C-P-R the baby was breathing through the mouth,” the witness said.

The three-year-old and 32-year-old are in a stable condition.

Major Crash investigators are examining what caused the vehicle to leave the road and are appealing for witnesses.

Police are urging anyone who saw the crash, or the silver Toyota Kluger travelling in the area beforehand, to contact police.