Robert Bales is to be charged with 17 counts of murder

An American soldier accused of gunning down Afghan civilians in the middle of the night, Robert Bales, is to be charged with 17 counts of murder.

The shooting spree in Kandahar province earlier this month sparked outrage in Afghanistan, and led to calls for Nato to speed up its planned withdrawal of troops.

Staff Sergeant Bales is the only known suspect in the killings, despite repeated Afghan assertions that more than one American was involved.

The BBC's Jonathan Blake reports from Washington.