Dropping the “mother of all bombs” on Islamic State (ISIS/ISIL) jihadists in Afghanistan was “necessary to break” the terrorist group, declared U.S. Secretary of Defense James Mattis.

On April 13, Gen. John Nicholson, the top commander of U.S./NATO troops in Afghanistan, ordered American troops to drop the GBU-43/B Massive Ordnance Air Blast Bomb (MOAB) on a network of tunnels and caves in eastern Afghanistan’s Nangarhar province that facilitated ISIS attacks on U.S. troops and their Afghan counterparts.

The munition’s deployment on ISIS targets in Nangarhar’s Achin district, located along the Pakistan border, marked the first time the munition was used in battle.

U.S. troops have been fighting the ISIS branch in Afghanistan, known as the Khorasan Province (ISIS-K), since it established a foothold in the war-ravaged country in January 2015.

The United States fight against the terrorist group has intensified in recent weeks. Speaking to reporters in Tel Aviv Thursday, Secretary of Defense James Mattis said he had been regularly getting updates on the battle.

“In Afghanistan, they [U.S. forces] have been engaged in that fight up in that corner [Nangarhar’s Achin district] against ISIS elements up there for some time. I was kept informed, sometimes on a daily basis, of how the fight was going, of what the options were,” said the retired Marine Gen. Mattis.

“There was no surprise in terms of the effect of that battle at all. The battle was going on, and we were going to use what was necessary to break ISIS. And we’ve made that very clear in every theater where we’re up against ISIS,” declared the Pentagon chief.

Although Afghan officials have revealed that the MOAB killed more than 90 ISIS-K jihadists, the U.S. secretary of defense refused to provide a precise body count.

“Frankly digging into tunnels to count dead bodies is probably not a good use of our troops’ time when they’re chasing down the enemy that’s still capable,” proclaimed Secretary Mattis, adding, “For many years we have not been calculating the results of warfare by simply quantifying the number of enemy killed.  You all know of the corrosive effect of that sort of metric back in the Vietnam War.”

Mattis went on to say that “if you were to look at World War II and consider that if there’s a lot of casualties, then the war must be going terribly, then the last three months of World War II would have been the worst days of the American war because of what was going on.”

The GPS-guided 21,600 pound MOAB bomb is reportedly capable of demolishing everything within one square mile.

ISIS-K jihadists have been dramatically degraded, from a peak of 3,000 to about 700 now.

Moreover, the fairly small territory the group once held, namely four districts in Nangarhar as of July 2016, has also been reduced to primarily two districts.

Nevertheless, ISIS-K still poses a threat to stability in Afghanistan. U.S. troops are reportedly still fighting the terrorist group near the site where the MOAB was dropped.

Unlike his predecessor, President Donald Trump has granted commanders on the ground greater freedom to act independently.

“We give parameters to our subordinate commanders in the field,” Mattis told reporters in Tel Aviv Thursday. “When you’re in a conflict situation, you have got to … delegate initiative to those that you consider competent to do so, to carry out the authorities that you’re giving them.”

“I will not get into what authorities are delegated, because those are the specific things that allow for the urgency and the speed of operations in the field,” he added.

Asked if commanders on the ground consider the strategic effects of their actions, Mattis replied, “I have no doubt they do and if they didn’t, I’d remove them.”