The killings occurred a day after U.S. Secretary of State Mike Pompeo made a quick visit to the Afghan capital of Kabul where he said Washington was hopeful of a peace deal before Sept. 1.
It's not clear if the deaths were the result of the war, which at nearly 18 years is America's longest running. More than 2,400 U.S. service personnel have died in Afghanistan since the U.S.-led coalition invaded in October 2001 to oust the Taliban and hunt down al-Qaeda chief Osama bin Laden following the Sept. 11, 2001, attacks on the United States.
Efforts to find a peaceful end to Afghanistan's protracted war accelerated last year with the appointment of U.S. peace envoy Zalmay Khalilzad, who will begin a fresh round of direct talks with the Taliban on Saturday in the Middle Eastern state of Qatar, where the religious movement maintains a political office.
Khalilzad has held a series of meetings in Kabul as well in an effort to reschedule an Afghan-to-Afghan round of talks, which were scuttled earlier this year because neither side could agree on participants.
The Taliban have refused to hold direct talks with the Afghan government calling them U.S. puppets, but have said they would talk with members of the government if they arrive at the meeting as ordinary Afghans.
Before leaving Afghanistan for India, Pompeo on Tuesday underscored Khalilzad's strategy in the talks, which involves four interconnected issues: counterterrorism, foreign troop presence, inter-Afghan dialogue and a permanent cease-fire.
The U.S. military statement announcing the killings of the U.S. personnel was a terse two-paragraph announcement. It also said the identities of the soldiers would not be released until their families had been notified.