Two American troops were killed in Afghanistan on Wednesday, as potentially decisive talks between the US and the Taliban on the future of the war-racked country are set to resume.
US officials said the two service members died in combat from small-arms fire.
The names of the US service members killed in action were being withheld until after their relatives were notified, Nato officials said.
They had been part of Resolute Support, the US-led Nato mission in Afghanistan.
It brings the total number of US troops killed in Afghanistan this year to 17. Last month three Americans were killed in Tarin Kowt.
Zalmay Khalilzad, the US special envoy to Afghanistan, has flown to Doha and says he is ready to conclude peace talks with the Taliban.
The negotiations are expected to focus on establishing a timeline for the US withdrawal in exchange for a reduction in violence and a Taliban pledge not to protect ISIS or Al Qaeda.
Mr Khalilzad concluded the eighth round of talks with the Taliban last week, and seemed optimistic when he tweeted that he hoped this would be the final year that Afghanistan is at war.
The conflict began nearly 18 years ago after the September 11 attacks on US soil. A US-led coalition invaded the country to oust the Taliban.
The State Department said this week that Mr Khalilzad will travel to Afghanistan from Qatar to work on setting up talks between the Taliban and the Afghan government.
US President Donald Trump said US forces have been stuck in Afghanistan acting like a "police force".
Mr Trump wants most of the 13,000 troops withdrawn from Afghanistan before November 2020, when he will seek re-election.
But he has acknowledged that some will have to stay.
"We have to have a presence, yes," Mr Trump said this week. "The Taliban does not respect the Afghan government. It is a dangerous place and we have to keep an eye on it."
But a quick withdrawal of US troops could face resistance on Capitol Hill, where some fear the move could create a power vacuum that would intensify the civil war and give ISIS, Al Qaeda and other extremists room to grow.
Since the war began, about 2,300 American soldiers have died and more than 20,400 have been wounded.
The number of deaths fell sharply after 2014, when the Nato mission was no longer a combat operation.
Most of the US troops in Afghanistan, down from a peak of about 100,000, are training and advising Afghan soldiers.