Mr. Trump, after meeting at the White House with executives from seven major defense contractors, said the companies had already agreed to quadruple their production of what Mr. Trump referred to as "'Exquisite Class' Weaponry," in an apparent reference to sophisticated air defenses and cruise missiles. He said the increase would come "as rapidly as possible" to "the highest levels of quantity," though it was not clear how long such a ramp-up would take and how much the initiative went beyond a similar one that the administration announced in January.
"We have a virtually unlimited supply of Medium and Upper Medium Grade Munitions, which we are using, as an example, in Iran, and recently used in Venezuela," Mr. Trump continued in a post on social media.
Iran has fired thousands of drones and hundreds of missiles at U.S. forces and other targets in the Persian Gulf, rapidly reducing the stocks of expensive air defense interceptor missiles available to the United States and its allies. At the same time, the United States has fired longer-range weapons, like Tomahawk cruise missiles, at Iran, denting stocks of sophisticated munitions that are time-consuming and expensive to produce.
Some national security experts argue that the extensive use of such weapons -- likely what Mr. Trump referred to as "Exquisite Class" -- could divert resources that are necessary to deter China from trying to take control of Taiwan.
"If this were to go on for months, and we're using the same kind of munitions, we'd start having real challenges," said Jerry McGinn, the director of the Center for the Industrial Base at the Center for Strategic and International Studies, a Washington-based think tank.
Analysts say that Iran's air defenses and missile launchers appear to be getting depleted and destroyed enough to reduce the U.S. need to launch its most sophisticated weapons. And the United States does, indeed, have large stockpiles of the less expensive, airdropped precision bombs that the military can increasingly use as its warplanes fly deeper into Iranian airspace, they say.
"Our munitions status only increases as our advantage increases," Defense Secretary Pete Hegseth said on Thursday.
But the level of urgency in the Pentagon's need for more weapons depends in large part on defense planners' assessment of the need to deter China. In a war with China over Taiwan, the United States could quickly run through its stocks of air defense missiles to protect American military bases and aircraft carriers in the Pacific, said Michael O'Hanlon, the director of research at the Brookings Institution's foreign policy program.
"These trend lines are enough to get through the immediate crisis," Mr. O'Hanlon said, arguing that the United States and its allies had the munitions to manage Iran's dwindling ability to fire at targets in the Gulf. "It really boils down to the China question."
The breadth of the U.S. campaign against Iran, coupled with Mr. Trump's military interventions in Venezuela, Nigeria, Yemen and elsewhere over the last year, has given a new impetus to the long-running debate in Washington about the adequacy of U.S. weapons stocks and the defense industry's ability to produce more.
The American military has used an array of weaponry and systems in the Iran war so far, including Tomahawk cruise missiles fired from warships, 2,000-pound bombs fired from B-2 stealth bombers and a slew of precision missiles fired from fighter jets.
As part of the stated effort to sink the Iranian Navy, American submarines have also taken to firing heavyweight torpedoes. And multiple-rocket launchers known as HIMARS have fired precision missiles at Iranian military bases. The U.S. military has also used some weapons in combat for the first time, including cheaper attack drones and short-range ballistic missiles.
After Mr. Trump's meeting with defense contractors on Friday, one of them, Lockheed Martin, confirmed that the company had agreed to step up critical munitions production, an effort that began months ago and will play out over years. The company reached a deal with the Trump administration to increase production of PAC-3 missile interceptors to 2,000 per year by 2030 from about 600 per year.
A Lockheed Martin spokeswoman said that the company was moving with urgency, adding that the new agreement on Friday covered a range of munitions, not just the PAC-3s.
It was not the first time the Trump administration has met with defense contractors and demanded an increase in weapons production. In January, Mr. Trump issued an executive order that threatened to limit executive pay and prohibit stock buybacks and dividend payouts at defense companies that have not made capital investments or are deemed "underperforming."
How the administration will pay for any additional weapons it says it needs, especially amid the war with Iran, is not clear. Top Republicans have said in recent days that Pentagon officials are weighing sending them a supplemental funding request, but have received little information about how much the Pentagon would need or how soon defense officials might formally make the request.
Depending on the size of the request, such a vote could present Republicans with a politically wrenching choice before the November midterm elections. While most have been broadly supportive of Mr. Trump's military operations against Iran, many Republicans had also embraced the anti-interventionist "America First" foreign policy that he had promoted on the campaign trail and would prefer to avoid an on-the-record vote endorsing billions of dollars for an entanglement abroad.
At the same time, underscoring how messy an intraparty battle over a funding bill could quickly become, some senior Republicans in positions of power on Capitol Hill have long been urging the White House to ramp up spending on munitions. That includes Senator Mitch McConnell of Kentucky, the chairman of the subcommittee responsible for funding the Pentagon.
Republicans provided the Pentagon with roughly $153 billion in additional funding in their marquee tax cuts bill passed last summer. Defense Department officials told Congress in a report in February that they intended to spend it within the next year, including $24 billion on munitions such as medium-range missiles though some on Capitol Hill were weighing whether the administration could redirect some of those funds to meet more immediate needs.
Senator Andy Kim, Democrat of New Jersey, said administration officials told lawmakers during a closed-door briefing on Capitol Hill this week that the campaign in Iran was going to stretch on for some time.
"The sheer volume is going to deplete a lot of our stocks; it's going to require a lot of resupply," said Mr. Kim, who worked on the National Security Council under President Barack Obama. "Undoubtedly this is going to be something that leaves us at a significant shortage, and I worry about our ability to keep up with other concerns and threats around the world."
Helene Cooper and Tyler Pager contributed reporting.