A US plan to boost the production of Patriot air defence missiles, which Ukraine uses against Russian attacks, using Japanese factories is being delayed due to a shortage of a critical Boeing-manufactured component, according to four sources speaking to Reuters.

Mitsubishi Heavy Industries (MHI) 7011.T in Japan, which currently produces around 30 PAC-3 missiles annually under a license from defense contractor Lockheed Martin LMT.N, can increase production to approximately 60 missiles, as reported by two Japanese government officials and two industry sources to Reuters.

The US aims to raise global production from roughly 500 to over 750 Patriot missiles annually as soon as possible, according to a source familiar with the program. However, officials and industry sources stated that no expansion in Japan would be feasible without an increased supply of the missiles' seekers, which are crucial for guiding them in the final stages of flight.

"It could take several years before MHI is able to raise output" because of the shortage, said one of the industry sources to Reuters.

The production delay in Japan highlights Washington's challenges in incorporating global allies into its supply chains. Boeing is expanding its US seeker factory to boost production by 30%, but it won't be operational until 2027.

Lockheed Martin plans to increase US Patriot interceptor output from 500 to 650 by 2027, with each costing around $4 million. However, expanding Japan's PAC-3 missile production beyond 60 units annually would require Mitsubishi Heavy Industries (MHI) to increase its capacity.

In its 2022 plan to double military spending, Japan's government announced it would provide financial assistance to defense companies looking to expand production. However, these subsidies are limited to equipment intended for Japan's Self Defense Forces and do not cover exports.

As a result, either Mitsubishi Heavy Industries (MHI) or the United States would need to finance the construction of a new PAC-3 factory, which could cost tens of millions of dollars or more, according to one of the Japanese government sources.

"The Indo-Pacific is a large area of focus for the U.S. and our allies and strategically postured capabilities in the region are critical to support deterrence and maintain readiness," Lockheed Martin said in an email, referring questions about PAC-3 production in Japan to the Japanese and US governments, and MHI.

A $4.5 billion contract with the US Army, back in June, is set to boost production of Patriot missiles and seekers. Japan and US defense and foreign ministers will meet in Tokyo to discuss enhancing industrial cooperation, with the Patriot project being a key focus. Supply chain bottlenecks, however, continue to challenge US efforts to supply Ukraine with necessary munitions and air defense systems.

Ukraine needs 25 Patriot Systems for airspace protection: Zelensky

Ukrainian President Volodymyr Zelensky on Monday said that Kiev requires 25 Patriot air defense systems to fully safeguard its airspace, though he did not reveal the current number of Patriot systems the country possesses.

"If I say how many more we need, it will become clear how many we already have. I can tell you how many Patriots we need ... We need 25 systems to completely cover the skies over Ukraine," Zelenskyy told reporters.

Zelensky also said that Ukraine requires additional Western air defense systems beyond the US-made Patriots.

For months, Ukraine has been requesting seven additional Patriot systems to defend against Russian strikes two and a half years into the war.

NATO chief Jens Stoltenberg urged alliance members to continue their support for Kiev, warning that a Russian victory would pose the "greatest risk" to the US-led military bloc.

"The outcome of this war will shape global security for decades to come," Stoltenberg emphasized.

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