An Afghan official confirmed the deaths and injury on Saturday stemmed from an attack by an Afghan soldier, who also died.
The Pentagon didn't provide details about what led to the deaths of the US soldiers. It said the incident was under investigation.
A spokesman for the provincial governor in Nangarhar province, Attahullah Khogyani, said in a statement that the attack took place in the Achin district.
The Taliban claimed responsibility for the attack. Taliban spokesman Zabihullah Mujahid says in a statement that a Taliban loyalist had infiltrated the Afghan army "just to attack foreign forces".
In March, an Afghan soldier was killed after he opened fire on foreign forces at a base in Helmand province, wounding three US soldiers.
White House spokesman Raj Shah told reporters travelling with the President Donald Trump in New Jersey that Trump was "following the emerging situation in Afghanistan".
