The strike using the Massive Ordnance Air Blast bomb, or MOAB, was carried out Thursday morning against an Islamic State group tunnel complex carved in the mountains that Afghan forces have tried to assault repeatedly in recent weeks in fierce fighting in Nangarhar province, Afghan officials said.
U.S. and Afghan forces have been battling the Taliban insurgency for more than 15 years. But the U.S. military brought out the biggest conventional bomb in its arsenal for the first time to hit the Islamic State, which has a far smaller but growing presence in Afghanistan. That apparently reflects President Donald Trump's vow for a more aggressive campaign against the group.
The bomb — known officially as a GBU-43B but nicknamed the "mother of all bombs" — unleashes 11 tons of explosives. Pentagon video showed the bomb striking a mountainside overlooking a river valley with a giant blast that overwhelms the landscape and sent up a massive column of black smoke. Agricultural terraces are visible in the footage, but no population centers.
The Afghan Defense Ministry said in a statement that the bomb destroyed several IS caves and ammunition caches.
Gen. Daulat Waziri, a ministry spokesman, said 36 IS fighters were killed, and that the death toll could likely rise. He said Afghan forces were at the tunnel complex assessing the damage.
The Islamic State group's Aamaq news agency denied that any of its fighters were killed or wounded, citing a source within the group.
Waziri said the bombing was necessary because the complex was extremely hard to penetrate, with some tunnels as deep as 40 meters (over 130 feet). He called it a "strong position," with troops attacking it four times without advancing, adding that the complex "was full of mines."
"This was the right weapon for the right target," said U.S. Gen. John W. Nicholson, NATO commander in Afghanistan, at a news conference. He added that there were no reports of civilian casualties.
Nicholson said the bomb was intended to eliminate the militants' sanctuary in southern Nangarhar, "and this weapon was very effective in that use."
The office of President Ashraf Ghani said there was "close coordination" between the U.S. military and the Afghan government over the operation, and they were careful to prevent any civilian casualties.
But the massive blast still terrified villagers 20 miles away across the border in Pakistan.
Pakistani villagers living near the frontier said the explosion was so loud they thought a bomb had been dropped in their village by U.S. warplanes targeting militants in Pakistan.
"I was sleeping when we heard a loud explosion. It was an earsplitting blast," said Shah Wali, 46, who lives in the village of Goor Gari, 15 kilometers (9 miles) from the border with Nangarhar. "I jumped from my bed and came out of my home to see what has gone wrong in our village."
Dozens of other villagers also came out of their homes, Wali said. He later went near the border, where he met with other residents. He said he could see smoke in the sky.
"The whole house was shaking," said Mufti Khan of Achin district in Nangarhar. "When I came out of my house, I saw a large fire and the whole area was burning."
Another Achin resident, Mohammad Hakim, approved of the strike.
"We are very happy, and these kinds of bombs should be used in future as well, so Daesh is rooted out from here," he said, using the Arabic acronym for the Islamic State group.
"They killed our women, youths and elders, sitting them on mines," Hakim added. "We also ask the Kabul government to use even stronger weapons against them."
The U.S. estimates 600-800 IS fighters are in Afghanistan, mostly in Nangarhar. The U.S. has concentrated on fighting them while also supporting Afghan forces against the Taliban.
Trump called Thursday's operation a "very, very successful mission."
"I want a hundred times more bombings on this group," said Hakim Khan, a 50-year-old a resident of Achin.
Inamullah Meyakhil, spokesman for the central hospital in eastern Nangarhar province, said no dead or wounded had been brought to the facility from the attack.
District Gov. Ismail Shinwari added that there was no civilian property near the location of the airstrike.
The Site Intelligence Group, which tracks extremist organizations, reported Friday on a statement from the Afghan Taliban that condemned the U.S. for its "terrorist" attack.
The statement said it is the responsibility of Afghans, not the U.S., to remove the Islamic State group from the country. The two militant movements are rivals.
The U.S. has more than 8,000 troops in Afghanistan, training local forces and conducting counterterrorism operations. In the past year, they have largely concentrated on thwarting a surge of attacks by the Taliban, who have captured key districts, such as Helmand province, which U.S. and British troops had fought bitterly to return to the government.