Four people have been killed after the car they were travelling in crashed into a tree.
Police said they came across the crash on the A436 in Ullenwood while on patrol shortly after 02:00 BST.
Four males were found dead inside a black Renault Clio, Gloucestershire Police said.
A spokesperson for the force said urgent work to identify all those involved and notify their next of kin was ongoing.
The road remains closed in both directions between the A417 Air Balloon roundabout and Seven Springs.
Anyone who has any information about the crash, or has any dashcam footage, has been asked to contact police.