Washington. Defense Secretary Pete Hegseth on Monday sought to calm concerns that US-Israeli strikes on Iran could spiral into a prolonged regional war, declaring, “This is not Iraq. This is not endless.”

Hegseth, joined by Air Force Gen. Dan Caine, chairman of the Joint Chiefs of Staff, delivered the Trump administration’s first formal news briefing since Saturday’s strikes. President Donald Trump has conducted several phone interviews with reporters but has not taken questions on camera and has released only two videos since the operation began.

Hegseth described the operation as having a “clear, devastating, decisive mission” to destroy Iran’s missile threat, target its navy, and ensure “no nukes.”

“No stupid rules of engagement, no nation-building quagmire, no democracy-building exercise, no politically correct wars. We fight to win, and we don’t waste time or lives,” Hegseth said.

He also suggested the US was not pursuing regime change following the killing of Iranian Supreme Leader Ayatollah Ali Khamenei.

“This is not a so-called regime change war, but the regime sure did change, and the world is better off for it,” Hegseth said.

The briefing came as the conflict intensified across the region. Iran and allied armed groups have launched missiles at Israel, Arab states and US military targets in the Middle East.

Four American troops have been killed in action, and Trump on Sunday predicted additional US casualties. Caine acknowledged Monday that further losses are possible.

“We grieve with you, and we will never forget you,” he said, addressing the families of the fallen service members.

In a sign of the widening turmoil, US ally Kuwait mistakenly shot down three American fighter jets during a combat mission as Iranian aircraft, ballistic missiles, and drones attacked. US Central Command said all six pilots ejected safely from the F-15E Strike Eagles and were in stable condition.

US officials have not outlined an exit strategy or indicated when the conflict might end. The death of Khamenei has cast uncertainty over the future of Iran’s leadership and heightened regional instability.

Making the case for the strikes, Hegseth blamed Iran for initiating decades of hostility.

“For 47 years, the regime has waged a savage, one-sided war against America,” he said. “Their war on Americans has become our retribution against their ayatollah and his death cult.”

Hegseth did not cite any imminent nuclear threat from Iran, reiterating that last summer’s joint US-Israeli strikes had “obliterated their nuclear program to rubble.” Instead, he pointed to ballistic missiles and drones as the primary justification for the current operation.

“Iran was building powerful missiles and drones to create a conventional shield for their nuclear blackmail ambitions,” he said.

He accused Iranian officials of stalling during negotiations with the United States before the strikes.

“The former regime had every chance to make a peaceful and sensible deal. But Tehran was not negotiating,” Hegseth said.

In an interview Sunday with The New York Times, Trump said the assault could last “four to five weeks.” Hegseth declined to specify a timeline.

“President Trump has all the latitude in the world to talk about how long it may or may not take — four weeks, two weeks, six weeks. It could move up. It could move back,” he said.

Trump said the US and Israel have struck hundreds of targets, including missile sites and naval facilities, claiming to have destroyed Iran’s naval headquarters and multiple warships.

Caine said the operation, dubbed “Epic Fury,” involved B-2 stealth bombers flying a 37-hour round trip, similar to last year’s strikes on Iranian nuclear facilities. He also highlighted the use of cyber capabilities that “effectively disrupted communications and sensor networks,” leaving Iranian forces unable to coordinate or respond effectively.

Without offering operational details, Caine said US forces delivered “synchronized and layered effects designed to disrupt, degrade, deny, and destroy Iran’s ability to conduct sustained combat operations.”

The Iranian Red Crescent Society reported at least 555 people have been killed in Iran during the US-Israeli campaign. Authorities say 11 people have been killed in Israel and 31 in Lebanon.