A senior US military official has told NBC News that the Nato soldier killed by an Afghan Local Police officer in the east of the country was an American.
Earlier two British troops were shot dead by an Afghan soldier.
16 Nato servicemen have been killed by Afghan Security forces so far this year.
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A terminally ill five-year-old boy led out the England team at Wembley with his "best friend" Jermain Defoe.
It comes as the country faces a major migrant crisis with more than 62,000 stranded including outside the port of Piraeus.
Regime change has unleashed sectarian and tribal urges and is tearing the country apart.