London  - Five British soldiers have been killed in a single incident in Helmand Province in southern Afghanistan, the Ministry of Defence in London said Wednesday.

The soldiers, three from the Grenadier Guards and two from the Royal Military Police, were all killed as a result of gunshot wounds sustained in an attack in the Nad-e'Ali district Tuesday afternoon.

The BBC quoted sources as saying that the soldiers were at a checkpoint at the time of the incident and fired upon by an Afghan policeman. The report has not been confirmed.

The incident is being investigated, a spokesman for Task Force Helmand. (dpa)