US Defense Secretary Pete Hegseth said that military operations against Iran would not lead to an "endless war," during a press conference on Monday, though he acknowledged that the operation would not be complete overnight. Hegseth said the aim was to destroy Tehran's missiles, navy, and other security infrastructure.

"This is not Iraq. This is not endless," Hegseth said.

It will take time to achieve US military objectives in Iran, and additional US casualties are expected, US General Dan Caine, the chairman of the Joint Chiefs of Staff, said on Monday, as the United States and Israel's strikes on Iran continued for a third day.

The Israeli-US strikes on Iran as part of operations Roaring Lion and Epic Fury expanded on Monday with no end in sight. The US military said Kuwait's air defenses had mistakenly shot down three American F-15E fighter jets during an Iranian attack.

"This is not a single overnight operation. The military objectives that CENTCOM and the Joint Force have been tasked with will take some time to achieve, and in some cases will be difficult and gritty work," Caine told reporters. He added that the United States continued to send additional troops to the Middle East, even after a massive military buildup.

US Secretary of Defense Pete Hegseth and Chairman of the Joint Chiefs of Staff General Dan Caine hold a briefing amid the US-Israeli conflict with Iran, at the Pentagon in Washington, March 2, 2026.
US Secretary of Defense Pete Hegseth and Chairman of the Joint Chiefs of Staff General Dan Caine hold a briefing amid the US-Israeli conflict with Iran, at the Pentagon in Washington, March 2, 2026. (credit: REUTERS/ELIZABETH FRANTZ)

Caine's comments come a day after US President Donald Trump suggested that strikes against Iran could go on for the next four weeks.

Fourth US service member dies on Monday

A fourth US service member died on Monday of injuries sustained in the US operation against Iran. US military forces have intercepted hundreds of ballistic missiles targeting the US and its partners in the region.

In the biggest US foreign policy gamble in decades, President Donald Trump launched the campaign alongside Israel on Saturday against a foe that had tormented the United States and its allies for generations.

Even with the strikes, the conservative clerical leaders in Iran have shown no sign of yielding power. Military experts say US and Israeli air power, with no armed force on the ground, may not be enough to drive them out. Meanwhile, scores of Iranians have been reported killed in strikes, including several that hit apparent civilian targets.