Washington on Friday “welcomed” the very rare decision taken by Tokyo to send Patriot air defense missiles to the US from Japan to “replenish the stocks” of the US armed forces, which have been severely depleted by aid that provide Ukraine.

The American president Joe Biden he is “grateful” to the Japanese prime minister Fumio KishidaJake Sullivan said in a White House press release, estimating that this decision will contribute “to the security of Japan”, since it will “ensure that the US maintains a credible deterrence and response capability”.

To allow the transfer, Japan, which has very strict controls on arms exports under its constitution, relaxed the rules for the first time in nearly a decade.

The shipment of ammunition for the Patriot systems, which play a key role in the defense of Ukraine, marks the first time Japan has exported lethal items since the end of World War II, according to media reports in the Asian country.

The transfer of the missiles “will contribute (…) to international peace and security and also strengthen cooperation with allies and the US in the field of security,” the Japanese government said in the document announcing the decision.

Under the new rule, Japan “will be able to export domestically produced weapons with permission from a foreign state” to that particular state, an AFP source in the Japanese government’s national security affairs department said on condition of anonymity.

In particular, Japan produces Patriot Advanced Capability-3 (PAC-3) missiles under license from the American Lockheed Martin, which developed them.

The US, the main supplier of equipment to Ukraine’s military, is now turning to allies that have US-designed or US-made equipment to meet its needs.

US President Biden has asked the US Congress to approve a 61 billion euro funding package as soon as possible to continue providing military and economic aid to Kiev while replenishing the reserves of the US armed forces.

But negotiations with the opposition Republicans, who hold the majority of seats in the House of Representatives, will not be completed as the White House had hoped within the year.