The men, in the war-torn region as part of the K-For peacekeeping force, could face murder charges if they are found to have been "reckless or negligent", said an MoD spokesman.

A Special Investigation Branch team are in Kosovo gathering evidence about the shootings, which happened on 3 July.

Official reports on the incident say the patrol from 1st Battalion, the Parachute Regiment, opened fire on the vehicle because they feared lives were at risk from a man firing celebratory shots into the air from the roof of the car.

But eye-witness accounts have said the paratroopers did not do enough to warn the people in the car and no attempt was made to stop the vehicle.

An MoD spokesman confirmed an investigation is under way and said: "There is a possibility obviously that if they were found to be in any way shape or form to have been reckless or negligent then they could find themselves charged with murder."

He added: "They haven't been charged, they are still serving and are on active duty. They haven't even been cautioned."

The rules of engagement in Kosovo are similar to those used in Northern Ireland. All K-For soldiers carry a Green Card, allowing them to kill in self defence, but only after a verbal warning has been given.

Shoot to kill

British Army soldiers are trained in Northern Ireland to a required standard called the Yellow Card. This specifies when minimum force can be used and when lethal force can be used as a last resort.

A soldier may fire if he perceives himself, a colleague or civilian, to be in imminent danger. He must identify a weapon, such as a firearm or a car running a roadblock if it is driving at a civilian or soldier or has terrorists on board.