President Donald Trump set off a firestorm last Saturday night when he announced the U.S. strikes he ordered had “obliterated” Iran’s nuclear sites.

He and his top aides have only doubled down on the phrase since, even as the claim has become the focus of expert debate, political criticism and headline news coverage.

Trump acknowledged the controversy his language sparked as he spoke at the NATO summit on Wednesday, where he defended his description in the face of a preliminary U.S. intelligence analysis that Tehran’s nuclear program was only set back by a few months.

“The original word that I used, I guess it got us in trouble because it’s a strong word, it was obliteration,” Trump said. “And you’ll see that and it’s going to come out. Israel is doing a report on it, I understand.”

He went on to call it “total obliteration” and “virtual obliteration.”

Description at odds with early US intel, Joint Chiefs chairman

The U.S. strikes, carried out on the night of June 21, targeted three facilities: Isfahan, Natanz, and Fordo. They were hit with massive, 30,000-pound bunker-buster bombs in what was the largest B-2 strike in U.S. history.

“Tonight, I can report to the world that the strikes were a spectacular military success. Iran’s key nuclear enrichment facilities have been completely and totally obliterated,” Trump said as he addressed the nation from the White House over the weekend.

But one key player said the total scope of the damage wasn’t immediately clear.

Gen. Dan Caine, chairman of the Joint Chiefs of Staff, said on Sunday it was “way too early” to know the full damage, though he said all three sites sustained “extremely severe damage and destruction.”

On Tuesday, reports surfaced about a leaked initial assessment by the Defense Intelligence Agency with the help of U.S. Central Command.

According to two people familiar with the initial report, the bombing sealed off the entrances to two of the nuclear sites but that most of the damage was done to structures above ground, leaving the lower structures intact. The assessment also found that at least some enriched uranium had been moved from the nuclear sites ahead of the blasts and that centrifuges are largely intact.

The findings, though, are expected to evolve with time as more information is collected.

Trump’s “obliterated” description was cited by several top House Democrats criticizing that an administration intelligence briefing for lawmakers set for Tuesday was suddenly pushed until later in the week.

“We can only speculate as to why the Administration canceled the briefing, but it certainly appears as though they’re afraid to answer questions about their policies and the President’s unverified claims that the strikes obliterated Iran’s nuclear program,” Reps. Gregory Meeks, Jim Himes and Adam Smith said in a joint statement.

Democratic Sen. Mark Warner of Virginia, vice chair of the Senate Intelligence Committee, said he had a “lot of questions for the administration” about the U.S. strikes.

“I can tell you there was plenty of debate in the open domain about whether bunker-buster bombs alone could take out Iran’s facilities,” Warner said. “We also have got questions about where all of Iran’s enriched uranium is located at this point and if it’s not taken out, what next? Are troops still in harm’s way?”

Trump and Hegseth pushed back heavily on the initial report on Wednesday.

The president said the Defense Intelligence Agency “presented a report that wasn’t finished.”

“Since then, we’ve collected additional intelligence,” Trump said at NATO. “We’ve also spoken to people who have seen the site and the site, the site is obliterated.”

“The report said what it said, and it was fine,” he added. “It was severe, they think, but they had no idea. They shouldn’t have issued a report until they did.”

Trump was also confident that Iran wasn’t able to move its uranium stockpile before the U.S. strikes on their nuclear sites, despite images showing trucks lined up at Fordo in the days leading up to the attack.

“I think all of the nuclear stuff is down there because it’s very hard to remove, and we did it very quickly,” Trump said.

In pushing back against the report, Trump quoted Iran’s foreign ministry saying Wednesday that the country’s nuclear facilities had been “badly damaged.” Trump also emphasized the assessment of Israel’s Atomic Energy Commission, which said the U.S. strike on Fordo rendered it “inoperable.”

Hegseth, who joined Trump at the international gathering, said the 30,000-pound bombs resulted in “devastation underneath Fordo.”

“Any assessment that tells you it was something otherwise is speculating with other motives,” Hegseth added. “And we know that because when you actually look at the report, by the way, it was a top secret report, it was preliminary, it was low confidence.”

Standing at Trump’s side, Hegseth echoed, “Iran’s nuclear program is obliterated.”

ABC News’ Lalee Ibssa contributed to this report.