The latest fatalities, which bring to four the number of US soldiers killed so far this year in Afghanistan, underscore the difficulties in bringing peace to the war-wrecked country even as Washington has stepped up efforts to find a way to end the 17-year war, the longest for the United States, Al-Jazeera reported.
The US and NATO Resolute Support mission announced that the names of the service members killed in action were being withheld until after notification of the next of kin, in accordance with the US Department of Defense policy.
The statement also did not specify the location of the combat or say who the soldiers were fighting.
"The incident is under investigation and we have no additional information to provide," said Sgt 1st Class Debra Richardson, a Resolute Support Spokeswoman.
There are about 14,000 US forces in Afghanistan, supporting embattled Afghan forces as they struggle on two fronts - facing a resurgent Taliban which now holds sway over almost half the country and also the Islamic State of Iraq and the Levant (ISIL or ISIS) affiliate, which has sought to expand its footprint in Afghanistan even as its self-proclaimed "caliphate" has crumbled in Syria and Iraq.
The US removed the Taliban from power in the 2001 invasion following the September 11, 2001 attacks in New York and Washington.
But the Taliban subsequently regrouped while Washington shifted its attention to Iraq's Saddam Hussein, and by 2009, the war had become a stalemate.
The Pentagon has recently been developing plans to withdraw up to half of the American forces still in the country while at the same time stepping up efforts and having the US negotiate with the Taliban.
US envoy Zalmay Khalilzad, the Donald Trump administration's main negotiator with the Taliban, concluded earlier this month a 13-day marathon session with leaders of the armed group.
Following several rounds of talks, held in Qatar where the Taliban maintains an office, Khalilzad said the two sides reached two "draft agreements" covering the withdrawal of US troops and guarantees that Afghanistan would not revert to a haven for "terrorists".
But he was unable to persuade the Taliban to launch talks with the Afghan government. The Taliban has consistently refused to hold dialogue with the government in Kabul, describing it as a "US puppet".
The two sides seem to be in agreement about the withdrawal of American forces, but divided over the timeline and whether a residual American force would remain.
Last year, 13 US service members were killed in Afghanistan. Source: farsnews