Details of the incident, which is still under investigation, were not released.
Two more troops were wounded in the apparent attack July 7 according to an announcement from Resolute Support public affairs.
It was not immediately clear who carried out the attack, or whether they had been apprehended.
#WorldCupWith360nobs: Colombia Coach Jose Pekerman Accuses England Players Of Diving
Harry Kane had given England the lead from the penalty spot and Colombia's chance of qualifying for the quarter-finals looked slim.
North Atlantic Treaty Organisation did not release the identity of the American soldier killed or provide further details about where the incident took place.
But a police officer told news agency AFP the shooting happened at the airport in Tarinkot, the capital of Uruzgan province - although they were unable to confirm this detail with any North Atlantic Treaty Organisation officials.
Pompeo said the USA will "support, facilitate, and participate in these discussions", but emphasized negotiations with the Taliban must be "Afghan-led and Afghan-owned".
Beryl becomes first named Atlantic hurricane of 2018
The front will then stall over the region on Sunday producing more scattered showers and storms on and off throughout the day. After that, it will track through the northern Caribbean and head towards Haiti and the Dominican Republic.
The U.S. military believes its operations in the Achin district, site of the "Mother of All Bombs" drop on ISIS caves in 2017, has severely damaged the Islamic State's logistics in Afghanistan and thwarted its planned assaults on Kabul and Jalalabad.
The attack comes a year after three United States special forces soldiers were shot dead by one of their Afghan colleagues. They did not indicate a specific location where the attack occurred.
The latest incident comes as Lieutenant General Scott Miller is set to become the next commander of USA and North Atlantic Treaty Organisation forces in Afghanistan. The last insider attack that resulted in a U.S. casualty occurred two months earlier, in June of previous year.
Samsung profit misses estimates in second quarter
This likely means that the foldable smartphone's unveiling , which has been delayed for a few years, will finally happen soon. Although the moniker " Gear S4 " certainly has its charm, it will reportedly arrive as the " Galaxy Watch ".