An adult and two children have died and a fourth person is in a critical condition after a crash near Dalby on Queensland's Western Downs.
Police say two teenage children — a girl and a boy — were killed after a ute crashed into the rear of the sedan they were travelling in.
A man driving the sedan was also killed.
A second adult is being treated at the scene for life-threatening injuries.
The male driver of the utility was taken to Dalby Hospital with non-life-threatening injuries.
Emergency crews were called to the incident at Jimbour East, about 250 kilometres west of Brisbane, shortly after 11am on Monday.
Senior Sergeant Greg Wheeler said the incident was devastating.
"You know, a family basically here one minute, not the next — it's very difficult to fathom how it's actually occurred," he said.
He urged people to take extra care on the road.
"Pay attention to what you're doing, follow all the 'fatal five' rules.
"Life's pretty short and can disappear pretty quick, so please be careful."
Dalby Jandowae Road remains closed, and motorists are being urged to avoid the area.
The Forensic Crash Unit is at the site and is investigating.
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