Japanese Defense Minister Yasukazu Hamada (L) and US Defense Secretary Lloyd Austin (2nd from R) hold talks at the Pentagon on Sept. 14, 2022. (Kyodo)

WASHINGTON -- The Japanese and US defense chiefs on Wednesday agreed their nations will undertake joint technological research to counter hypersonic weapons, as they work to closely align their national security strategies amid China's growing assertiveness in the region.

The talks between Japanese Defense Minister Yasukazu Hamada and his US counterpart Lloyd Austin at the Pentagon -- their first in-person meeting since Hamada's appointment last month -- came amid heightened tensions over Taiwan following US House of Representatives Speaker Nancy Pelosi's recent trip to the self-ruled island.

"China's coercive actions in the Taiwan Strait and in the waters surrounding Japan are provocative, destabilizing and unprecedented," Austin said at the outset of the meeting, apparently alluding to China's increased military activities in response to the high-profile US visit to Taiwan in early August.

Hamada and Austin also strongly criticized China's launch of ballistic missiles as part of large-scale exercises near Taiwan last month, some of which fell into Japan's exclusive economic zone, as a "serious" incident that affects Japan's security and the safety of the public, according to the Japanese Defense Ministry.

"The two ministers affirmed that a unilateral change in the status quo by force is unacceptable in the Indo-Pacific region" confirming their countries will "cooperate closely and seamlessly" toward preventing any such attempts, the ministry said.

While making clear their security strategies are on the same page, Hamada and Austin agreed to engage in "concrete" efforts to bolster the bilateral security alliance in areas where they can.

The areas include technologies to defend against hypersonic missiles amid an intensifying arms race with China and Russia.

Hypersonic weapons are designed to travel at more than five times the speed of sound. Detection and defense against them is challenging because they can maneuver en route to the target and fly at lower altitudes than conventional ballistic missiles, according to experts.

A Japanese government official said the focus of the envisaged joint research will be on technologies and components that would be necessary for the development of missiles that can intercept hypersonic weapons.

The two countries also decided to jointly analyze information to be collected by the US military's MQ-9 reconnaissance drones that will be temporarily deployed to a Japanese Maritime Self-Defense Force air base in Japan's southwestern prefecture of Kagoshima.

During the talks, Hamada said Japan's resolve to fundamentally bolster its defense capabilities through a planned update of its national security documents and with a substantial increase in its defense budget.

Austin showed "strong" support for Japan's plan, Hamada told reporters.

The defense capabilities that Japan is currently examining include an ability to attack missile-launching sites in enemy territory, which the Asian country has so far opted against acquiring under the post-World War II pacifist Constitution.

Japan plans to update its National Security Strategy by the end of this year, reflecting the region's increasingly challenging security environment. It would be the first revision of the long-term security and diplomacy policy guideline since it was adopted in 2013.

In March, the US Defense Department unveiled an outline of its own National Defense Strategy, calling China its "most consequential strategic competitor" and vowing to prioritize the challenges posed by China over those by Russia.

China considers Taiwan a breakaway province to be reunified with the mainland, by force if necessary. The island is viewed as a potential military flashpoint that could draw the United States into conflict with China.

A Taiwan contingency is also of particular concern for Japan given the proximity of its islands in the southwest -- including the Senkakus, a group of East China Sea islets controlled by Tokyo but claimed by Beijing.

Austin reaffirmed the "unwavering" commitment of the United States to the defense of Japan, including extended deterrence backed by the "full range" of US nuclear and conventional defense capabilities.

He also reiterated the US stance that the Senkaku Islands, called Diaoyu by China, fall within the scope of the Japan-US security treaty, meaning Washington would come to Tokyo's aid in the event of an armed attack against the uninhabited islets, according to the Japanese official. (Kyodo)