Derbyshire Police have said two children who died in a crash near Creswell in Derbyshire yesterday were just five years old and 22 months old.
The collision, between a Peugeot 106 and a Citroen C2 on the B6042, left their mother and seven-year-old sister with minor injuries.
The family, from the Worksop area, were travelling towards the A60 when their Peugeot collided with the Citroen, which was being driven in the opposite direction.
The driver of the Citroen, a 23-year-old woman from Worksop, suffered an arm injury.
Derbyshire Police are urging spokesman urged anyone with information to contact the force's witness appeal line on 01773 572 929.