The three military members were killed on Tuesday in a roadside bombing near the city of Ghazni, the USA military said, in what appeared to be the deadliest attack on us forces in Afghanistan in the last 17 months.
The incident took place on 27 November, Resolute Support, the official name of the North Atlantic Treaty Organisation mission, said in a statement.
An American contractor was also wounded in the attack in Ghazni. "The wounded service members and contractor were evacuated and are receiving medical care". The names of the dead and the injured were not immediately released.
The deaths are the latest in a growing toll on US forces in Afghanistan following the death of an army Ranger following an operation against al Qaeda militants in Nimruz province on Saturday.
The U.S. military announced the death of Army Ranger Sgt. Leandro Jasso, 25, on Saturday.
Resolute Support said that "an initial review indicates Sgt. Jasso was likely accidentally shot by our Afghan partner force" and "there are no indications he was shot intentionally".
Foreign Minister Shah Mahmood Qureshi on Tuesday strongly condemned the killing of three U.S. soldiers in an improvised explosive device (IED) attack in Ghazni city of Afghanistan.
Three US service members killed in Afghanistan blast
In the past several weeks, the insurgents also have launched assaults on villages in rural districts of the province that are populated by minority ethnic Hazara Shiites.
General Scott Miller, the top USA and North Atlantic Treaty Organisation commander in Afghanistan, said Jasso was killed "defending our nation, fighting Al Qaeda alongside our Afghan partners".
"Sgt. Jasso was killed defending our nation, fighting al Qaeda alongside our Afghan partners", he added.
A total of 13 United States troops have been killed this year in Afghanistan, according to the Defence Post.
That attack came a few days after a suicide bomber killed 55 religious scholars gathered in the Afghan capital, Kabul, to celebrate the holiday marking the birth of Islam's prophet, Muhammad.
This is the second attack in a month targeting U.S. forces in the region.More news: New Tariffs Could Hit Laptops, iPhones, Trump Says
More news: Copa Libertadores final delayed after Boca bus attacked by rival fans
More news: NASA's InSight lands on Mars after six-month journey