A soldier with the NATO-led force in Afghanistan shot and killed an Afghan policeman in a car that was driving toward a NATO patrol at high speed.

Soldiers warned the approaching vehicle with hand signals, a mini flare and warning shots, but it continued its approach toward the convoy, NATO’s International Security Assistance Force said in a statement Sunday.

Troops opened fire at the car, mortally wounding a passenger who officials later discovered was an Afghan police officer.

The incident happened Saturday in Lashkar Gah, the provincial capital of Helmand province.

“This was an unfortunate incident but I do not blame the foreign forces,” said Helmand’s police chief Col. Asadullah Sherzad.

NATO convoys fearing potential suicide bombers periodically fire on approaching cars. Many NATO vehicles have red and white warning signs telling drivers to stay back.