A man and two nine-year-old boys suffered "life-threatening injuries" in a crash on the A84 in Stirlingshire.
The crash occurred on the Callander to Strathyre stretch of the road at about 17:15 on Sunday.
The man, aged 54, and boys were travelling in a Volkswagen Golf which collided with a Citroen Berlingo. They were taken to Queen Elizabeth University Hospital in Glasgow.
A 30-year-old woman travelling in the Citroen was also seriously injured.
A two-year-old girl also in the Citroen was uninjured, but was taken to Forth Valley Royal Hospital as a precaution.
Insp Andrew Thomson appealed for information about the "serious road traffic collision involving multiple casualties".
