SINGAPORE (Kyodo) -- Japanese Defense Minister Shinjiro Koizumi on Sunday pledged to strengthen his country's defense capabilities and security cooperation across the Indo-Pacific, rejecting China's criticism that the buildup represents a "new militarism."

Addressing the Shangri-La Dialogue security forum in Singapore, Koizumi said the regional security environment is growing increasingly challenging amid economic coercion, military pressure and intensifying competition in the cyber, space and information domains.

"The boundary between peacetime and contingency is becoming increasingly unclear," he said.

Koizumi defended Japan's defense modernization, including a planned revision of key national security documents by the end of this year and investments in areas such as artificial intelligence, unmanned systems, cyber capabilities and space.

"There is a country that has a huge arsenal of nuclear weapons and strategic bombers. Japan has neither of such weapons. And yet, Japan is labelled new militarism. Isn't it strange?" he said in an apparent reference to China's criticism of Japan.

The defense minister argued that Japan's reputation as a peace-loving nation, built since the end of World War II, would not be undermined by what he called false claims.

He also warned, "Opaque military buildups and action without clear intentions will be the cause of distrust and miscalculation," adding that Japan will carry out its defense update "with a high degree of transparency."

At the same time, Koizumi stressed that Tokyo remains committed to dialogue with Beijing despite persistent differences between the two neighbors.

Tokyo-Beijing relations have deteriorated to their lowest level in years after Prime Minister Sanae Takaichi suggested last November that Japan could respond in support of the United States if China attacked Taiwan, a self-governed island Beijing views as a renegade province to be brought into its fold by force if necessary.

Koizumi expressed disappointment that he did not have an opportunity to meet Chinese Defense Minister Dong Jun at the forum. Dong skipped the Shangri-La Dialogue for a second straight year, with China sending a lower-level delegation instead.

Koizumi also pointed to disruptions to shipping through the Strait of Hormuz, saying they underscored the importance of keeping critical sea lanes open and secure.

He highlighted growing security cooperation with the United States, Australia, the Philippines, Britain and Southeast Asian nations, and said Japan would take on a larger role in defense equipment and technology cooperation following its easing of arms export restrictions in April.

"Division weakens deterrence. Unity strengthens deterrence," Koizumi said.

On the sidelines of the forum, Koizumi agreed with his Philippine counterpart Gilberto Teodoro to work to realize Japan's export of its Maritime Self-Defense Force's Abukuma-class destroyers promptly after decommissioning and of one of its TC-90 training aircraft by March 2028, his ministry said.

During Koizumi's visit to Manila in early May, the two agreed to set up a framework for working-level talks on such exports, potentially the first case under Japan's eased arms export rules.

With Singapore's Chan Chun Sing, Koizumi told reporters that their countries will also set up a working group for cooperation in areas such as maritime, air, cyber and space domains, the defense industry, and information sharing.