UK forces in Afghanistan have shot dead two civilians and injured a child.
An international military spokesman said a patrol opened fire after a van travelling at high speed failed to stop north of Girish in Helmand province.
He said the vehicle failed to respond to hand signals from troops, adding that the incident was deeply regrettable and was being investigated.
UK troops assumed responsibility for Nato operations in Helmand province earlier this year.
A spokesman for the International Security Assistance Force (Isaf) said medical staff administered first aid and the casualties were taken to Camp Bastion.
"Isaf deeply regrets the loss of life and injury to civilians," he said.
"It is not known why the vehicle failed to stop when clear signals were given, and a full and thorough investigation into the circumstances of the incident has commenced."
UK-led forces have faced stiff military opposition from Taleban-led militants.
More than 3,700 people, about 1,000 of them civilians, have died in violence in Afghanistan since the beginning of 2006, the authorities say.
Seventeen of those killed were British soldiers.