Could the US run low on weapons for its assault on Iran? 

Leaks from the Pentagon last week – as reported by media in the United States – have suggested that if strikes on Iran continue for more than 10 days, US stocks of some critical missiles could start to run low.

On Saturday, the US and Israel launched strikes on Iran while talks between Washington and Tehran over Iran’s nuclear programme and other issues, understood to include limiting Iran’s holding of ballistic missiles and ending its arming of regional armed groups, were ongoing.

Iran hit back with missile and drone attacks across the region, including targets in Israel as well as US military assets in Bahrain, Saudi Arabia, Qatar, the United Arab Emirates and Iraq.

The Pentagon, the headquarters of the US Department of Defense, is also understood to have warned President Donald Trump that an extended military campaign in Iran would carry serious risks, including the high cost of replenishing Washington’s dwindling munitions stockpiles.

Trump has held that the US has enough in its stockpile to keep the military campaign in Iran going.

“The United States Munitions Stockpiles have, at the medium and upper medium grade, never been higher or better – As was stated to me today, we have a virtually unlimited supply of these weapons. Wars can be fought ‘forever,’ and very successfully, using just these supplies,” Trump wrote in a Truth Social post on Tuesday.

While Trump said on Monday that the plan for the Iran war was initially “projected four to five weeks” but could go on for longer than that, analysts have told Al Jazeera that some weapons in its stockpile may have run very low by then, particularly crucial interceptor missiles.

Here is what we know.

What weapons is the US using in its attacks on Iran?

According to the US military’s Central Command (CENTCOM), it has used more than 20 weapons systems across air, sea, land and missile defence forces during its ongoing operation in Iran.

The US is using B-1 bombers, B-2 stealth bombers, F-35 Lightning II stealth fighters, F-22 Raptor jets, F-15s and EA-18G Growlers.

It is also using drones and long-range strike systems, including the Low-Cost Unmanned Combat Attack System (LUCAS) one-way drones, MQ-9 Reaper drones, M-142 High Mobility Artillery Rocket Systems (HIMARS) and Tomahawk Cruise Missiles.

Additionally, it is using air defence systems such as the Patriot, Terminal High Altitude Area Defense (THAAD) batteries and Airborne Warning and Control System (AWACS) aircraft.

Two US aircraft carriers, the USS Abraham Lincoln and the USS Gerald R Ford, were in the Middle East when the attack on Iran began.

The Wall Street Journal reported on February 23 that Pentagon officials and General Dan Caine, chairman of the joint chiefs of staff, had warned Trump about the dangers of a prolonged campaign against Iran.

At the same time, The Washington Post reported that Caine had told Trump that a lack of critical munitions and support from regional allies could hinder efforts to contain a possible Iranian retaliation in the event of an attack by the US.

US munitions stockpiles, including those used in missile defence systems, have been stretched thin by their use in support of allies such as Israel and Ukraine, according to the report.

Trump lashed out at media reports that Caine had issued such a warning, adding that the general “believed” in a war with Iran.

How much weaponry did the US use up in strikes on Iran last year?

Iran fought a 12-day war with Israel from June 13 to 24 in 2025. The US joined the campaign on the side of Israel, bombing several Iranian nuclear facilities towards the end of it. During this time, the US deployed two of its advanced THAAD missile defence system batteries to Israel.

THAAD is a Lockheed Martin-made advanced missile defence system that uses radar and interceptor missiles to shoot down short-, medium- and intermediate-range ballistic missiles at distances of about 150-200km (93-124 miles).

After the 12-day war, US officials reported that they had to fire more than 150 of these missiles to intercept incoming Iranian missiles, multiple news reports said, accounting for about 25 percent of its THAAD interceptors.

According to US media reports, the US also ran out of large numbers of ship-borne interceptors during the war last year.

Which weapons could the US run out of now?

If the war with Iran continues, the most likely US shortages would be in precision, high-end munitions and interceptors like the THAAD, analysts say.

This includes the Joint Direct Attack Munitions (JDAMs), which are guidance tools that use the Global Positioning System (GPS) to turn unguided bombs into precision-guided munitions, effectively making “dumb” bombs “smart”.

A THAAD battery usually comprises 95 soldiers, six truck-mounted launchers, 48 interceptors (eight for each launcher), one radar system and a fire-control and communications component. There are nine active THAAD batteries worldwide as of mid-2025, according to Lockheed Martin.

In 2024, Al Jazeera’s Mike Hanna reported from Washington, DC, that one THAAD battery costs between $1bn and $1.8bn.

Interceptors and munitions take months to assemble, integrate and test. It then takes additional time to transport by sea and air and set up and deploy them.

Experts say high-end missile defence systems are primarily designed to deal with limited, high-intensity attacks from states such as Russia, China or North Korea in mind, rather than from prolonged, large barrages of cheaper missiles.

Over time, finite stockpiles of advanced interceptors will run down at very high cost, analysts say, as each interception can cost hundreds of thousands or even millions of dollars to take down a missile that may only have cost a few thousand dollars to build.

Speaking to the press on Monday, US Secretary of State Marco Rubio said Iran is able to churn out many more offensive weapons than the US and its allies can build interceptors to stop them.

“They are producing, by some estimates, over 100 of these missiles a month. Compare that to the six or seven interceptors that can be built a month,” Rubio said.

“They can build 100 of these a month, not to mention the thousands of one-way attack drones that they also have. They’ve been doing this for a very long time. And by the way, they’ve been doing it under sanctions.”

Additionally, stocks of Standard Missile-3 (SM-3) are already running out due to slow production, strikes on Yemen’s Houthi rebel group and earlier clashes with Iran. The SM-3 is an antiballistic missile interceptor launched from warships.

The US is not only depleting weapons, but also losing weapons due to miscalculations in the campaign. For instance, on Sunday, at least three US jets were shot down in Kuwait, in what US officials described as a friendly-fire incident.

How soon could the US run out of interceptors?

Christopher Preble, a senior fellow at the US think tank, Stimson Center, told Al Jazeera that while the US can afford the financial cost of the war given its trillion‑dollar defence budget, the real constraint is stockpiles of interceptor missiles, such as Patriot and SM‑6.

Preble warned that high interception rates cannot continue indefinitely.

“It is reasonable to speculate that the pace of operations right now, in terms of numbers of interceptions, could not continue indefinitely, certainly, and perhaps could not continue for more than several weeks,” he said.

Manufacturing replacements is not instantaneous. “A Patriot missile or an SM-6 … is a very complicated piece of equipment,” he added.

Preble said he could not comment on how long it takes to manufacture the weapons.

“It’s not like they’re cranking them out, hundreds or thousands a day. That’s not the pace of manufacturing.”

What happens if the US runs low on some weapons?

Preble said the US could continue to manufacture weapons or move them to the Middle East from other deployments.

“Some of these interceptors are used or were intended to be sent to Ukraine to deal with Russian strikes on Ukraine,” he said.

“Some of them are used in Asia, in the Indo-Pacific, not currently used, but they would be important in the event of a contingency in the Indo-Pacific. So there would be some concern with removing those weapons from that theatre.”

How much is this war costing the US?

While the Pentagon has not disclosed how much the war is costing the US, estimates suggest that sustaining it will be extremely costly.

Reports by Anadolu news agency suggest the US spent about $779m in the first 24 hours of its operation in Iran, with a further $630m for the pre-strike build-up – moving aircraft, deploying more than a dozen naval vessels and mobilising regional assets.

The Center for a New American Security estimates it costs approximately $6.5m per day to operate a carrier strike group such as the USS Gerald R Ford.