Japan's Self-Defense Forces during a military parade. (Kyodo News Agency)

Japan's Armed Forces in their current state are unable to protect the country from emerging global challenges and rising geopolitical threats, Chief of Staff of the Japanese Joint Staff General Yoshihide Yoshida said on Tuesday.

"We cannot maintain Japan's security with our current capabilities," Yoshida told Nikkei Asia.

He pointed out that the government approved three military documents to improve the Self-Defense Forces (JSDF), and confirmed an established roadmap to increase the army's budget to 2 percent of GDP.

"There are two things Japan must do. First, we must fundamentally strengthen our defensive capabilities so that we are not underestimated. Second, we need to do what we can to sustain extended deterrence, including through strategies involving US nuclear weapons," Yoshida added.

During a state visit made by South Korean President Yoon Suk Yeol to Washington in March, Yoon announced after a meeting with US President Joe Biden the establishment of a Nuclear Consultative Group (NCG); a new US-ROK platform to jointly plan and execute the American nuclear umbrella (nuclear deterrence assets).

But so far, South Korea has yet to publicly approve Japan's participation in the NCG, and its Defense Minister Deputy Shin Beom Chul ruled out the possibility.

The DPRK warned earlier that the three allies are forming a "NATO-style nuclear alliance" and stressed that the rising of US-led military blocs in the Asia-Pacific might expose humanity to grave dangers.

Tokyo passed three defense documents last year as part of plans to boost the army's capabilities: the National Security Strategy, National Defense Strategy, and Defense Plan.

According to the documents, the government will increase the defense budget over the span of the next five years, from $187.8 billion now to around $294 billion, to match NATO's standard requirement of 2 percent GDP army spending.

China, Russia, and the DPRK are at the center of Tokyo's updated defense papers passed in 2023. The 510-page assessment claimed that these three countries contribute to "the most severe and complex security environment since the end of World War II."

The National Security Strategy was perceived as a departure from Japan's postwar self-defense-only concept.