Defense Secretary Pete Hegseth on Thursday said the U.S. military bomb strikes on three Iranian nuclear facilities had "significantly damaged [Iran's] nuclear program" and "set it back by years" in a confrontational news conference called to counter an early intelligence assessment from the Defense Intelligence Agency that said Iran's program had been set back only by months.

Hegseth described news reports about the leaked DIA report as "half-truths" intended "to cause doubt and manipulate" and instead said he would focus on what he called the "bottom line" of Saturday's strikes involving seven B-2 stealth bombers that dropped 14 massive ordnance penetrators on two of the three Iranian sites.

"President Trump directed the most complex and secretive military operation in history, and it was a resounding success, resulting in a ceasefire agreement and the end of the 12-day war" in Iran, Hegseth said.

"Because of decisive military action, President Trump created the conditions to end the war, decimating – choose your word – obliterating, destroying Iran's nuclear capabilities."

Asked twice during the briefing about enriched uranium that may have been moved from nuclear sites before the attack -- a key outstanding question as the intelligence community assesses post-strike realities -- Hegseth said the Pentagon was "watching every aspect" and did not say the U.S. believed it was under rubble at the sites.

But he said he hasn't reviewed any intelligence "that says things were not where they were supposed to be," whether "moved or otherwise."

The director general of the UN's nuclear oversight agency, Rafael Grossi, has said he believes the material was moved from the sites before the attacks.

Hegseth lashed out against news media reporting about the early DIA assessment and said it was a "re-strike report" intended to gauge whether a site would need to be hit again.

Gen. Dan Caine, chairman of the Joint Chiefs of Staff, standing next Hegseth, referred questions about damage assessments to the intelligence community.

Hegseth said Caine told him in the White House Situation Room "that the first reports are almost always wrong."

"They're almost always incomplete," he said Caine told him.

The defense secretary appeared to read from the preliminary DIA assessment that he said "admits itself, in writing, that it requires weeks to accumulate the necessary data to make" the assessment it made.

That assessment was made with "low confidence," according to Hegseth, and was not coordinated with the broader intelligence community.

Hegseth said the DIA report was based on a "linchpin assumption," which, he said, means "your entire premise is predicated on a linchpin" and "if you're wrong, everything else is wrong."

Caine, who had noticeably refrained from repeat Presdient Trump's "obliterated" claim at a Sunday news conference the morning after the strikes, told reporters Thursday that "the Joint Force does not do [battle damage assessments] … the intelligence community does."

Instead, he focused on tactical details and seemingly described a mission that unfolded without a hitch.

Describing "what we know," Caine said "the weapons functioned as designed, meaning they exploded." Planners "accounted for everything," the chairman said.

"We know that the trailing jets saw the first weapons function and the pilots stated, quote, 'This was the brightest explosion that I've ever seen. It literally looked like daylight.'"

Hegseth told reporters it was "my lane" as the top civilian leader at the Defense Department, to "do politics." He said it was part of his job to "translate and talk about those types of things."

"So, I can use the word 'obliterated.' He could use 'defeat, destroyed,' [and] assess all of those things."

When asked, "Have you been pressured to change your assessment or give a more rosy intelligence assessment to us by any political factors, whether it's the president or the secretary? And if you were, would you do that?" Caine said that was an "easy" question to answer.

"I've never been pressured by the president or the secretary, to do anything other than tell them exactly what I'm thinking," he said. "And that's exactly what I've done."