A 12-year-old girl has died in a collision on the M61 near Chorley.
Police closed the motorway in both directions when a Vauxhall Corsa collided with a Nissan Qashqai at aound 10.45pm last night.
The incident occurred between junction eight and the Bolton West/Rivington services.
The 12-year-old girl, who was a passenger in the Qashqai, died at the scene.
She has since been named as Sana Patel, from Blackburn.
Five other people travelling in the Qashqai suffered minor injuries.
Read more: Transport news from Blog Preston
Those believed to have been travelling in the Corsa fled the scene on foot and enquiries are now underway to trace them.
Supt Andy Cribbin, of Lancashire Police, said: “First and foremost our thoughts are with the family and friends of Sana.
“There are no words to describe what they will be going through and we send them our deepest condolences at this incredibly difficult time. They are currently being supported by specialist officers.
“Our investigation is in the early stages and we are working hard to establish exactly what occurred, and to locate the people who were in the Corsa.
“We are now appealing directly to them. We know the car is registered to an address in West Yorkshire and we are appealing for the driver and any passenger at the time of the collision to make contact with us as soon as possible.
A twelve year old girl has tragically lost her life, so we would urge them to search their conscience and do the right thing by contacting us.
“We are also asking anybody who saw the collision, or saw either vehicle in the moments before it happened, to get in touch with us as soon as possible.”
Anybody with information is asked to get contact police on 101, quoting log 1817 of July 6th.
The M61 was closed in both directions between junctions six and eight while collision investigators attended the scene and reopened at around 9am this morning.