The U.S. military said it conducted a strike on an ISIS-K tunnel complex in the Achin district of Nangarhar province, Afghanistan, on Thursday.

A U.S. aircraft dropped a GBU-43 Massive Ordnance Air Blast, also known as a MOAB, as part of ongoing efforts to defeat ISIS-Khorasan in Afghanistan, according to a statement from U.S. Central Command. 

The strike aimed to minimize the risk to Afghan and U.S. forces conducting clearing operations in the area, the release said.

"As ISIS-K's losses have mounted, they are using IEDs, bunkers and tunnels to thicken their defense," Gen. John W. Nicholson, the top commander in Afghanistan, said in the release. "This is the right munition to reduce these obstacles and maintain the momentum of our offensive against ISIS-K."

The release said the U.S. took "every precaution" to avoid civilian casualties.

PhotosA look at the U.S.'s Massive Ordnance Air Blast (MOAB) bomb

The strike comes just days after a Special Forces soldier was killed in Nangarhar province. Staff Sgt. Mark De Alencar, of 7th Special Forces Group, was killed Saturday by enemy small arms fire while his unit was conducting counter-ISIS operations, according to the Defense Department. 

Staff Sgt. Mark De Alencar, a special forces operator with 1st Battalion, 7th Special Forces Group, was killed Saturday in a fire fight against ISIS forces in Afghanistan. (Photo credit: U.S. Army)

The fact that the U.S. dropped the MOAB in the same province where De Alencar was killed is probably not a coincidence, said Bill Roggio, of the Foundation for Defense of Democracies.

“There might have been a degree of payback here as well,” Roggio told Military Times. “There’s certainly nothing wrong with that, especially if you’re killing your enemy.”

ISIS has had a strong province in Nangarhar and three other Afghan provinces for years, said Roggio, also editor of the Long War Journal. The fact that the U.S. dropped the MOAB indicates that ISIS remains a threat in the area, he said. The weapon is also effective against enemy fighters who hide in caves.

“What it does is basically suck out all of the oxygen and lights the air on fire,” Roggio said. “It’s a way to get into areas where conventional bombs can’t reach.”

The U.S. mission in Afghanistan is twofold: to train and advise Afghan forces battling the Taliban, and target terrorists affiliated with al-Qaida and the Islamic State. The latter are centralized in Nangarhar province along the Pakistan border, where Thursday’s strike occurred.

The massive U.S. attack comes as several regional powers, including Russia, China, Iran and Pakistan, have begun to exert more influence — in some cases to undermine NATO's objectives.

On Wednesday, the White House announced it is conducting a broader strategy review intended to establish the United States' next steps for the 15-year Afghanistan campaign. As part of that, the president intends to dispatch his national security adviser, Army Lt. Gen. H.R. McMaster, to “find out how we can make progress alongside our Afghan partners.”

This story is developing. Check back for updates.