Two civilians have been killed and six others wounded in the southern Afghan province of Helmand today, the British military said. It was not immediately clear how the civilians were hurt, but local media said the casualties were the result of a foreign military air strike. The issue of civilian casualties has become the biggest source of tension between the Afghan government and its Western backers. Dozens of civilians have been killed in a string of erroneous air strikes in this year alone.

"This morning two dead and six injured civilians were brought to our medical facility near Naad Ali and the four most seriously injured were moved to our medical facility at Camp Bastion," Commander Paula Rowe, spokeswoman for the British army in Afghanistan said.

Naad Ali district is in Helmand, the main opium growing region where mostly British forces are engaged in daily gunbattles with Taliban insurgents.

Rowe said an investigation into the Afghan civilian deaths was underway and more information about the circumstances of their deaths would be released later in the day.

"We are always deeply saddened by civilian deaths irrespective of how it is caused," Rowe said.