The Pentagon is urgently pressing the U.S. defense industry to accelerate weapons production to replenish diminished munitions stockpiles, including those depleted during the ongoing five-month conflict with Iran.

Deputy Defense Secretary Steve Feinberg sent a memo to industry leaders on Wednesday demanding they submit plans within 21 days to "drive significantly faster, more aggressive delivery schedules and/or increased production for critical capabilities," according to a copy obtained by The Washington Post.

"Years-long development cycles are not acceptable," Feinberg wrote. "We must dramatically accelerate our program schedules and expand our production capacity now."

Pentagon spokesman Sean Parnell confirmed the memo in a statement Saturday, affirming it is "real" and saying it "will inform the fiscal year 2028 budget submitted to Congress for funding, and it is entirely consistent with our ongoing push to rebuild the defense industrial base." He added that the department was focused on boosting munitions acquisitions to provide "the weapons our warfighters need at the pace the threat demands," noting that efforts over the past week to speed the process are part of a broader modernization effort that predates the Iran conflict.

The push comes as recent fighting with Iran further depleted the U.S. military's already reduced stockpiles of advanced missile interceptors, potentially putting American forces at greater risk if hostilities resume, according to a new analysis from the Center for Strategic and International Studies (CSIS), a Washington-based think tank. The analysis found that shrunken inventories of Patriot and THAAD interceptors may compel the U.S. and its Middle Eastern allies to take greater risks to conserve those air defenses — for example, by launching fewer interceptor missiles against incoming Iranian drones and missiles, increasing the probability that one could penetrate defenses.

CSIS estimated last month that the number of Patriot interceptors fell from 2,330 before the war to 1,030 when the April ceasefire took effect. Following subsequent fighting, the stockpile is now estimated at between 759 and 827 — a decrease of at least 65% since the conflict began. THAAD interceptor numbers fell from 452 before the war to between 232 and 262 at the start of the April ceasefire. The U.S. was able to partially replenish that inventory to between 234 and 278 interceptors, though the stockpile remains at least 38% below pre-conflict levels.

President Donald Trump has pushed back against reports of a munitions shortage, posting on Truth Social Thursday that the U.S. has "massive amounts" and that "large amounts are being manufactured and shipped to the U.S. as needed."

The production directive arrives as a defense spending bill remains stalled in Congress. Lawmakers have voiced frustration over Trump's military action against Iran and are resisting the White House request to substantially increase Pentagon spending to $1.5 trillion, up from approximately $900 billion the prior year. The proposed increase would represent one of the largest peacetime defense budget jumps in U.S. history, and the memo's reference to the fiscal year 2028 budget signals that the acceleration plans are intended to shape funding requests Congress will debate in the coming months.