Japan must urgently strengthen its military, the defense minister said Tuesday, citing rising threats from China, North Korea and Russia.

His comment comes after a new government assessment once again highlighted the need to boost the country's military amid growing risks.

Japan is already beefing up military spending and security cooperation in Asia, deploying missile launchers to outer islands, moving to acquire "counterstrike" capabilities and easing rules on weapons exports.

But Shinjiro Koizumi said in a preface to the annual defense white paper that it was "imperative that Japan further reinforce and transform its defense capabilities with a stronger sense of urgency and crisis than ever before."

In the Asia-Pacific, "not only are China and North Korea further strengthening their military capabilities, China-Russia and Russia-North Korea are also reinforcing their cooperation," he added.

The new white paper said China was "intensifying its activities" in the region around Japan, "extending beyond the so-called first island chain to the second island chain."

It listed a series of incidents in 2025, including activities by Chinese aircraft carriers and the "unusual close approach" by Chinese aircraft to Japanese planes in two incidents in June and July.

Japanese jets scrambled 595 times in the year to March 31, 2026, including 366 sorties against Chinese aircraft and 214 for Russian planes.

This compares to 704 the previous year and was the fewest since at least 2021.

Japan decided in April to lift its self-imposed ban on weapons exports, but the white paper highlighted problems in the country's production base that could jeopardise procurement and innovation.

Koizumi also said that he and US counterpart Pete Hegseth had "exchanged candid views" on the "unwavering" US-Japan alliance, while also increasing security cooperation with the Philippines, Australia and South Korea to realise a "a Free and Open Indo-Pacific".

"As the security environment becomes increasingly and rapidly severe, what is required now is to strengthen resilience against crises all across the entire Indo-Pacific region," Koizumi said.

"In order to do so Japan will build and expand multilayered networks among allies and like-minded countries, and enhance interconnectivity with like-minded countries and others in every area."

China has expressed alarm at what it sees as a return to "new militarism" by Japan, with relations worsening since comments about Taiwan last year by hawkish new Prime Minister Sanae Takaichi.