Afghan officials said on Friday that 36 members of the Daesh terrorist group were killed on Thursday as the US military dropped what is considered to be the largest non-nuclear bomb on Afghanistan.
The target of the attack was a Daesh complex in the Momand Dara area, according to the Pentagon.
The GBU-43/B Massive Ordnance Air Blast bomb hit a "tunnel complex" in the Achin district of Nangarhar province, US Forces Afghanistan said in a statement.
The strike occurred at about 7:32pm local time (1502 GMT).
Pentagon spokesman Adam Stump said it was the first combat use of the weapon.
It was not immediately clear how much damage the device had done.
The security situation in Afghanistan remains precarious, with a number of militant groups trying to claim territory more than 15 years after the US invasion which toppled the Taliban government.
White House spokesman Sean Spicer opened his daily news briefing speaking about the use of the bomb and said, "We targeted a system of tunnels and caves that ISIS (Daesh) fighters used to move around freely, making it easier for them to target US military advisers and Afghan forces in the area."
Last week, a US soldier was killed in the same district as the bomb was dropped while conducting operations against Daesh.
"The United States takes the fight against ISIS (Daesh) very seriously and in order to defeat the group, we must deny them operational space, which we did," Spicer said.
He described the device as "a large, powerful and accurately delivered weapon." The United States took "all precautions necessary to prevent civilian casualties and collateral damage," he said.
US officials say intelligence suggests Daesh is based overwhelmingly in Nangarhar and neighbouring Kunar province.
Estimates of its strength in Afghanistan vary. US officials have said they believe the movement has only 700 fighters but Afghan officials estimate about 1,500.
A Daesh offshoot in Afghanistan is suspected of carrying out several attacks on religious minorities in the country.