The massive expenditure of U.S. munitions in the Middle East is increasingly worrying Asian allies and frustrating Pentagon officials overseeing the Indo-Pacific, who fear that the prolonged war with Iran could undermine U.S. readiness for a conflict with China as it continues to step up military pressure across the region.

Concerns about the depleted stockpile come as the United States canceled an amphibious landing exercise with South Korea scheduled for September, citing demands on U.S. forces from the war in Iran, a week after President Donald Trump announced that he was scaling back joint military exercises with the key ally.

South Korea and other U.S. partners in Asia, including Japan and Taiwan, rely on Washington as the dominant supplier of major conventional weapons and are reckoning with years-long backlogs. The Middle East conflict has intensified those strains, consuming and reallocating munitions that could be critical in a war with China.

One Taiwanese official said they expect “significant delays” of Pac-3 Patriot missiles due to the drain on supplies as the Pentagon has depleted most of its interceptor stockpile in the Middle East, describing the shift in focus from the Indo-Pacific as “troubling.”

In December, Beijing staged its largest-ever military drill around Taiwan, encircling the democratically governed island with ships and aircraft. Nearly $30 billion in U.S. arms approved for sale to Taiwan have yet to be delivered, including $882 million worth of Patriot missiles, according to Taiwan Security Monitor.

Japan has similarly been warned by the Pentagon of possible delays in defense shipments, including Tomahawk cruise missiles, according to an Asian diplomat familiar with the matter.

Current and former officials and diplomats spoke to The Washington Post on the condition of anonymity, citing the sensitivity of arms sales discussions and U.S. military supplies.

Japanese Defense Minister Shinjiro Koizumi said in May that delays were “possible” but there had been no change in Tokyo’s plans to acquire Tomahawk missiles. Taiwanese defense officials told Taiwan’s parliament in March that they still expect 102 Patriots to be delivered this year. The Financial Times reported in May that deliveries of 400 Tomahawks to Japan could be delayed as much as two years.

Japan’s Embassy in Washington and Taipei’s representative office in Washington did not respond to requests for comment. A Defense Department official said “the Joint Force remains postured, ready, and capable of deterring aggression” in the Indo-Pacific, adding that U.S. military resources, including naval forces, routinely move between combatant commands.

“It seems to me that the likelihood that [Taiwan is] going to get a whole 100 is pretty low. I think the number one priority for the United States, rightly, will be refilling its own stockpiles,” said Jennifer Kavanagh, director of military analysis at the Washington think tank Defense Priorities.

“The United States probably also feels like it owes Gulf state allies some replenishment. The war on Iran is not over,” she said.

The drain on weapons in Iran has become a source of tension between President Donald Trump and Defense Secretary Pete Hegseth, The Post has reported, though the president has repeatedly denied that U.S. weapons stockpiles are running low.

Officials at Pacific Command, which oversees U.S. military operations in Asia, have also expressed frustration over the shifting focus and dwindling resources available to deter Beijing, according to three people familiar with the matter.

One U.S. official said more than 30 ships that were supposed to be in the Pacific had been shifted to the Middle East during the war.

“It’s clear that they’re paying a big price, especially on the Navy side of things,” the official said.

This month, the Japan-based USS George Washington was diverted to the Middle East, relieving pressure on the USS Abraham Lincoln after concerns about the extended deployment and conditions for sailors aboard the ship.

The departure of the region’s last aircraft carrier underscores a broader diversion of U.S. forces from the Indo-Pacific, where China fields the world’s largest navy by number of vessels.

Since the Iran war began, the Pentagon has drawn down several advanced missile-defense systems including Patriot interceptors.

In April, Gen. Xavier Brunson, commander of U.S. Forces Korea, confirmed during testimony to the Senate Armed Services Committee that radars used in missile defense systems were taken from the Korean Peninsula ahead of U.S. strikes on Iran’s nuclear facilities in June 2025, and that additional munitions were moved this year. He said the THAAD interceptor system, the centerpiece of U.S. missile defense on the peninsula, remains in place.

Questions over U.S. military readiness in the region come as Trump is sending warmer overtures to top U.S. adversaries there: Chinese leader Xi Jinping and North Korea’s Kim Jong Un.

Trump has repeatedly said that Xi won’t invade Taiwan while Trump is president, though Beijing has never publicly stated as much. Trump recently described Kim as “unthreatening and respectful,” and said he expects to meet the North Korean leader this year.

A roughly $14 billion U.S. arms package for Taiwan was shelved ahead of Trump’s May summit in Beijing with Xi. The two leaders are expected to meet in Washington on Sept. 24.

One Chinese official said any signals that the White House will approve the package would “severely undermine” any further potential visits this year.

China has brushed off requests from the Pentagon’s top policy chief to visit China for discussions on the military relationship. For months, the undersecretary of defense for policy, Elbridge Colby, has in vain pushed for a meeting with Chinese defense policy planners, according to two diplomats familiar with the matter. China’s lack of interest was first reported by Politico.

Colby, alongside others in the White House and the Pentagon, has prodded Asian allies to shoulder more of their own defense costs. At a forum in the Philippines this month, he pushed back against any suggestion that the region is being deprioritized. “We are not leaving; in fact, we are digging in,” he said.

Allies have struggled with the contradiction of that pressure to spend more on U.S. arms while facing delays in delivery. “The situation is very challenging,” the Taiwanese official said.

Trump in May raised concerns in Taipei about his commitment to Taiwan when he described arms sales to the island as a “good negotiating chip” with China, though an $11 billion arms package approved by the president late last year represents the largest-ever single U.S. arms commitment to Taiwan.

Beijing has continued to ramp up military activity this year. Following its record-breaking military drills around Taiwan in December, China has expanded military infrastructure on disputed reefs in the South China Sea and squeezed Taipei with a spate of new coast guard drills near the island.

In July, Beijing also celebrated its first known test of a sea-based nuclear-capable missile, rattling the United States and its Asian allies.

“Beijing continues to manufacture its own reasons for increased drills and military pressure around the island,” said Craig Singleton, senior fellow at the Washington-based Foundation for Defense of Democracies, which tracks the frequency of Chinese incursions near Taiwan.

Questions about the state of U.S. munitions in the Indo-Pacific have sharpened since the start of the war in Ukraine. The U.S. has sent billions of dollars worth of weapons to support Kyiv, but of different types than those that would be needed in a long-range, maritime-heavy conflict in the Pacific.

The Iran war, however, has more directly impacted the Pentagon’s Asia deterrence posture, experts say.

“Between Iran and the western Pacific, there’s a lot of overlap,” said Mark Cancian, a retired Marine colonel and now senior adviser at the Washington-based Center for Strategic and International Studies, which has run dozens of war games since 2023 examining how quickly U.S. munitions could be depleted.

Those war games found that defending against an invasion of Taiwan would probably exceed current Pentagon supply plans and that many critical weapons would be exhausted within weeks.

“Even at the beginning of the war against Iran, we were likely inadequate for a conflict with China in the western Pacific,” said Cancian.

Xi has instructed China’s military to be capable of invading Taiwan by 2027, according to U.S. intelligence officials, though recent assessments say Chinese leaders do not currently have imminent plans to do so.

The theoretical deadline, however, underscores what analysts and officials say is a “window of vulnerability” in U.S. munition stores.

The Pentagon has pressed defense contractors to dramatically accelerate weapons production and awarded Lockheed Martin a $58.6 billion contract to triple Patriot interceptor production by 2030.

Beijing has not fought in a hot war since its 1979 conflict with Vietnam, but in the decades since, it has built a rapidly expanding arsenal of sophisticated ballistic, hypersonic and anti-ship missiles.

China’s defenses are far more advanced than Iran’s, making close-in attacks far riskier and increasing reliance on long-range missiles that can strike from safer distances. Across simulations run by CSIS, the U.S. generally expended 5,000 long-range missiles in just four weeks of conflict with China.

The Post reported that more than 850 Tomahawks were fired in the first four weeks of the Iran war. CSIS estimates that figure has since exceeded 1,000, from a prewar stockpile of between 3,100 and 4,500 missiles.

The Pentagon has depleted other key long-range munitions, including roughly a quarter of its prewar stock of Joint Air-to-Surface Standoff missiles and as much as three-quarters of its 90 Precision Strike Missiles, according to April CSIS figures.

Most critical, analysts say, is the rapid depletion of defense munitions, including THAAD and Patriot missiles, which have been deployed extensively in both Ukraine and the Middle East.

“They are the most critical because there are no good substitutes. When you run out of Patriots, when you’re out of THAADs, there’s no way you can stop missiles coming in,” said Cancian.

In an Indo-Pacific conflict, missile-defense interceptors would shield the roughly two dozen U.S. bases in Asia and tens of thousands of American troops in Japan and South Korea.

Analysts estimate that the U.S. has already expended most of its pre-Iran-war inventory of Patriots and THAAD interceptors, leaving only around 1,000, according to CSIS figures published in late July.

“China has 3,000 ballistic missiles or more. So that’s just bad math,” said Kavanagh.