The Pentagon is pressing major U.S. defense contractors to accelerate weapons production, issuing strict deadlines to replenish critical military stockpiles depleted during the conflict with Iran, according to newly disclosed Defense Department directives.

Deputy Defense Secretary Steve Feinberg wrote to industry leaders on Wednesday, giving them no more than 21 days to submit plans to drive significantly faster, more aggressive delivery schedules and/or increased production for critical capabilities, according to a memo obtained by The Washington Post.

“Years-long development cycles are not acceptable,” Feinberg wrote in the memo, demanding faster program schedules and an expansion of production capacity.

In a statement to Newsweek on Sunday morning, Pentagon spokesman Sean Parnell said that from day one under Defense Secretary Pete Hegseth, "this Department has been focused on delivering generational change to the speed, capacity, and lethality of America’s defense industrial base and the Arsenal of Freedom."

He continued: "Deputy Secretary Feinberg is a generational leader in that effort, driving the hard work of fixing our broken, antiquated, and immensely complex acquisitions system so we can actually produce the weapons our warfighters need at the pace the threat demands. Working directly with industry leaders to accelerate production is not new. It has been the clear intent of the President and this Secretary from the start."

Concerns Over Depleted Missile Defenses

The initiative underscores mounting concern within military planning circles that months of combat against Iran have significantly reduced inventories of key missile defense systems, such as Patriot and Terminal High Altitude Area Defense (THAAD) interceptors. Shrunken inventories of these interceptors may force the U.S. and its Middle Eastern allies to take more risks to conserve those air defenses, according to an analysis from the Center for Strategic and International Studies (CSIS), a Washington think tank. American forces may launch fewer missiles against incoming Iranian drones and missiles, raising the chance of one getting through.

According to the CSIS analysis, the number of Patriot interceptors fell from 2,330 before the Iran war to 1,030 when the April ceasefire took effect, and following recent fighting, the stockpile is now estimated to be between 759 and 827—a decrease of at least 65 percent since before the conflict began. Similarly, the number of THAAD interceptors fell from 452 before the war to between 232 and 262 at the start of the April ceasefire; while the U.S. was able to partially replenish the inventory to between 234 and 278 interceptors, the stockpile remains at least 38 percent smaller than it was before the conflict.

Restocking heavily depleted items—such as Patriot, THAAD, and Tomahawk cruise missiles—could take at least three years, even with elevated funding.

Costs and Administration Pushback

Hegseth informed senators last month that the war with Iran has cost an estimated $37.5 billion since hostilities began in late February, covering current operations and projected needs through the end of the fiscal year on September 30.

While President Donald Trump pushed back on reports of critical shortages, stating on Truth Social on Thursday that the United States maintains “massive amounts” of weaponry and that “large amounts are being manufactured and shipped to the U.S. as needed,” Pentagon officials maintain that the production push is essential to fortifying the broader defense industrial base. On Saturday, Parnell affirmed that Feinberg's memo is “real,” adding that it “will inform the fiscal year 2028 budget submitted to Congress for funding.”

Meanwhile, a defense spending bill is currently stalled in Congress, with lawmakers fuming over Trump’s military action against Iran and resisting the White House request to substantially increase Pentagon spending to $1.5 trillion, up from about $900 billion last year.

Contact Newsweek editors for this story: Steve Mollman and Anthony Murray.