The United States needs Japan's help to cope with strategic challenges in Europe and Asia that are straining its defense industries, the U.S. ambassador to Japan said on Monday as the countries kicked off talks on military industrial cooperation.

"Our national security strategy calls for us to be able to handle one and a half theaters, that's a major war and another one to a stand-off, and with both the Middle East, Ukraine, and keeping our deterrence credible in this region (East Asia) you can already see that we are in two plus," Rahm Emanuel told reporters.

On Sunday, Japan and the U.S. kicked off their first talks in Tokyo on forging deeper defense industry collaboration under the U.S.-Japan Forum on Defense Industrial Cooperation, Acquisition and Sustainment (DICAS) established in April by Japanese Prime Minister Fumio Kishida and U.S. President Joe Biden.

Discussions on Tuesday between U.S. Under Secretary of Defense for Acquisition and Sustainment William A. LaPlante and Masaki Fukasawa, the head of Japan’s Acquisition, Technology, and Logistics Agency, will focus on naval repairs in Japan that could help free up U.S. yards to build more warships.

"China has a major capacity we already know that will surpass us on new shipbuilding," Emanuel said.

Other potential cooperation between Japan and the U.S. includes aircraft repairs, missile production and military supply chain resilience, he added.

Japan and the U.S. already build a missile defense interceptor together and Tokyo has also agreed to supply Patriot PAC3 air-defense missiles to the U.S.