The Pentagon is pushing US defence companies to accelerate weapons production as the military seeks to replenish depleted stocks of munitions, including missile interceptors used during the ongoing war with Iran.

Pentagon spokesman Sean Parnell said on Saturday that the department was focused on increasing munitions purchases to provide troops with “the weapons our warfighters need at the pace the threat demands”.

Deputy Defence Secretary Steve Feinberg ordered defence industry leaders on Wednesday to submit plans within 21 days for significantly faster delivery schedules and increased production of critical weapons systems, according to a memo obtained by The Washington Post.

“Years-long development cycles are not acceptable,” Feinberg wrote, calling for a major expansion of production capacity and faster programme schedules.

Parnell confirmed the memo was authentic and said the push would feed into the Pentagon’s fiscal 2028 budget request to Congress.

He stressed that the effort was part of a broader initiative to rebuild the US defence industrial base that began before the five-month-old conflict with Iran.

The urgency has increased as recent fighting has further depleted US stocks of advanced missile interceptors.

A Centre for Strategic and International Studies (CSIS) analysis warned that reduced inventories of Patriot and THAAD interceptors could leave US forces and regional allies with fewer options to defend against Iranian missiles and drones if hostilities resume.

CSIS estimated that the US Patriot interceptor stockpile fell from about 2,330 before the war to between 759 and 827 following the latest fighting — a decline of at least 65%.

THAAD interceptor stocks also remain well below pre-war levels.

The inventory stood at about 452 before the conflict, fell to between 232 and 262 by an April ceasefire and has since recovered only to between 234 and 278, according to the analysis.

The reduced stocks could force US forces to be more selective in intercepting incoming Iranian missiles and drones, potentially increasing the risk that some weapons penetrate air defences.

President Donald Trump has rejected reports of a US munitions shortage, saying on social media on Thursday that the country had “massive amounts” of weapons and that additional supplies were being manufactured and shipped as needed.

Meanwhile, a defence spending bill remains stalled in Congress, where lawmakers have raised objections to Trump’s military action against Iran and resisted a White House request to increase Pentagon spending to $1.5 trillion from roughly $900 billion last year.