Trump promised to ‘bomb the s---’ out of ISIS. And then he did.

When he was running for president, Donald Trump famously vowed to “bomb the s---” out of the Islamic State. Despite a recent series of reversals on other foreign policy issues, he appeared to make good on that promise Thursday.

At 7:30 p.m. local time, the U.S. military dropped the most powerful non-nuclear bomb in its arsenal on a compound of Islamic State tunnels and caves in Nangarhar province in Afghanistan, near the Pakistani border.

The GBU-43/B Massive Ordnance Air Blast, also known as the “Mother of All Bombs,” had never been used in combat before. The Pentagon said it “took every precaution to avoid civilian casualties” with the strike, although it was unclear as of Thursday evening who’d been killed. The MOAB, which was developed and tested shortly before the 2003 U.S.-led invasion of Iraq, has a blast radius that stretches a mile in each direction.

The strike was intended to deliver maximum destruction to ISIS fighters and facilities with as little risk as possible to Afghan and American forces in the area, according to U.S. Central Command officials. The Islamic State has an estimated 600 to 800 fighters in Afghanistan, according to Pentagon spokesman Adam Stump. That the Pentagon would deploy the weapon indicates that military leaders see ISIS as an persistent threat in the area.

“As ISIS’ (Afghanistan affiliate) losses have mounted, they are using IEDs, bunkers and tunnels to thicken their defense,” Gen. John Nicholson, the commander of U.S. forces in Afghanistan, said in a statement. “This is the right munition to reduce these obstacles and maintain the momentum of our offensive.”

The 21,000-pound conventional bomb was dropped from the back of a U.S. Air Force C-130 cargo plane. While the U.S. had never used it before, the military had dropped more than 12,000 bombs on Afghanistan in President Barack Obama’s second term. In 2016, it dropped 1,337 bombs on the country.

The U.S. had previously used similar bombs to destroy the network of caves and tunnels used by al Qaida and the Taliban. Earlier this week, the Pentagon announced the death of 37-year old Mark Alencar, a Special Forces soldier killed in counter-ISIS operations in the same province.

[READ MORE: US drops more bombs in Obama’s final year of office than in 2015]

Trump declared Thursday’s bombing a “successful mission,” praising the military.

“If you look at what’s happened over the last eight weeks and compare that, really, with what’s happened over the last eight years, you’ll see there’s a tremendous difference,” he told reporters at the White House.

He declined to say whether he had been involved in the decision making.

“Everybody knows exactly what happened, so, and what I do is I authorize my military,” he told reporters. “We have given them total authorization . . . and frankly, that’s why they’ve been so successful lately.”

The president has granted military commanders broader control to authorize anti-terrorism operations as they intensify the fight against the Islamic State. According to the Pentagon, Nicholson signed off on Thursday’s mission.

[READ MORE: Trump warms to China and NATO as his foreign policy campaign pledges fall]

White House Press Secretary Sean Spicer repeatedly dodged questions about Trump’s involvement in and knowledge of the bombing.

“The United States takes the fight against ISIS very seriously, and in order to defeat the group we must deny them operational space, which we did,” he said.

Earlier this week, Trump announced that he was sending his national security adviser, Army Lt. Gen. H.R. McMaster, to Afghanistan to assess whether more U.S. troops are needed.

Nicholson told the Senate Armed Services Committee in February that several thousand more troops are needed to break the “stalemate” in their fight against the Taliban.

There are currently 8,400 U.S. troops in the country, conducting counterterrorism operations against insurgents and training and advising Afghanistan’s military. Another 6,400 troops from other NATO countries also are in Afghanistan. Last year, Obama announced that he would keep that number until the end of his term instead of dropping it to previously planned troop levels of 5,500 by early 2017.

Trump reportedly told Afghan President Ashraf Ghani in December that he would consider a troop increase to stop the country’s security from deteriorating. The 16-year conflict received little attention during his presidential campaign. Trump called the situation in Afghanistan “a mess” and said troops would probably have to stay there, “because that thing will collapse in about two seconds after they leave.”

Vera Bergengruen: 202-383-6036, @verambergen