Four men 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, near Cheltenham, while on patrol shortly after 02:00 BST.
Four people were found dead inside a black Renault Clio, Gloucestershire Police said.
A spokesperson for the force said urgent work to identify all those involved, who are aged 18 or over, and notify their next of kin was ongoing.
The road was closed in both directions between the A417 Air Balloon roundabout and Seven Springs. It has since reopened.
Anyone who has any information about the crash, or has any dashcam footage, has been asked to contact police.
Gloucestershire county councillor Paul Hodgkinson said there had been a number of fatal crashes on the road in recent years.
Posting on X, formerly Twitter, he said: “This is very sad. The A436 is an extremely busy road which has had accidents and some fatalities over the last few years.
“The Ullenwood Manor Road junction, in particular, has low visibility.”