"The strategy sends a clear message to the Taliban that they can not wait us out", he said.
That statement and an Afghan official, speaking on condition of anonymity due to the situation's sensitivity, said the attack occurred in Uruzgan province.
"The strategy has sent a clear message to the Taliban - they can not wait us out - and we are beginning to see the results both on the battlefield where the Taliban's momentum is slowing and in the prospects for peace with them", Pompeo said.
Commenting on the Saudi gathering, the Taliban urged the kingdom and the clerics to back the group in its war against US -led troops in the country, pledging to continue its insurgency until all foreign troops leave the country.
A service member has died in southern Afghanistan in what appears to be a green-on-blue attack, military officials announced Saturday.
The Taliban released a statement praising an Afghan soldier for carrying out the attack, without taking credit for it themselves. Two other Americans were wounded in the attack. "We're counting on all the actors in the region to be supportive of that", he said.
The Taliban went back to attacking government positions after three days, while the Afghan government formally concluded its own cease-fire on June 30.
"The Taliban continues to receive external support from regional actors, including Pakistan, Iran and Russian Federation", the report claimed.
The attack comes a year after three USA special forces soldiers were shot dead by one of their Afghan colleagues.
The Taliban released a statement saying an Afghan soldier fired on US troops in the province of Uruzgan, Reuters reported.
Some of the USA forces are involved in counterterrorism operations, particularly against the Islamic State jihadist group. ISIS is seen as an invading foreign force, its Afghan branch part of a major active threat to American and European security. But the Taliban ignored calls for extending the ceasefire and engaging in peace talks, and it has since returned to the battlefield with more intensity inflicting heavy casualties on Afghan security forces and seizing new territory.