TOKYO >> China’s moves to assert its territorial claims in the South China Sea are giving fresh impetus to Japanese plans to play a bigger role in regional security, adding to the growing strains between the two Asian rivals.

Japan said this week it is exploring whether it can accelerate a proposal to supply patrol boats for Vietnam, which is embroiled in a tense standoff at sea with China after Beijing moved an oil rig into disputed waters. In a similar deal, Japan agreed in December to lend 18.7 billion yen ($183 million) to the Philippines to purchase 10 Japanese-made boats.

The vessels are a tangible sign of Prime Minister Shinzo Abe’s effort to deepen ties with Southeast Asia in the face of China’s expanding maritime ambitions. He is likely to stress Japan’s commitment to regional stability in a speech to Asia-Pacific defense ministers in Singapore on Friday night.

"China’s recent behavior has enabled Abe to push cooperation in a much more conspicuous way," said Corey Wallace, a Japan and maritime security expert at the University of Auckland in New Zealand.

China claims nearly all of the South China Sea, bringing it into conflict with others in the region. The Philippines accused China in May of reclaiming land around a reef that both countries say is their own. The feuds mirror the dispute in the East China Sea over a group of uninhabited islands known as the Senkaku in Japan and the Diaoyu in China.

"What Japan is doing is being sympathetic to us, at the same time it’s also protecting its own interests, which is the Senkaku islands," Philippine Defense Secretary Voltaire Gazmin said in an interview in Manila.

The Philippines welcomes Japan’s expanded role, though the legacy of Japan’s brutal occupation of much of Asia before and during World War II make Gazmin wary of Japan going too far.

"We have to see," he said. "We will have to follow it up so the direction would not be toward what happened before."

Japan’s pacifist constitution limits what it can do beyond its own self-defense, but the patrol boats for coast guards technically fall under policing, not military assistance.

Japan is also playing a larger role in a U.S.-led disaster relief exercise in Southeast Asia. A Japanese military ship, the Kunisaki, is the lead vessel for the exercise for the first time. It departed the U.S. naval base in Yokosuka, Japan, on Thursday with 10 Australian and 130 U.S. troops aboard, headed for Vietnam, the Philippines and Cambodia.

Also, preparations are underway for a first-ever meeting between defense ministers from Japan and the Association of Southeast Asian Nations, Japan’s Chief Cabinet Secretary Yoshihide Suga said this week. ASEAN leaders were noncommittal when Abe first proposed the meeting in December, wary of angering China.

For Japan, it’s about both taking on more of the burden of its own defense, as the U.S. wants, and preparing for the possibility that that the U.S. may not be the dominant force it has been in the Pacific, not immediately, put perhaps 10 to 15 years from now, Wallace said.

"Japan wants to put into place frameworks for cooperation with other important players in the region that many years down the track, if nurtured, could provide a buffer or some relief if there is a slow relaxing of intensity in U.S. engagement," he said in an email response to questions.

The government has made maritime security a priority for its overseas development aid, though it totals just 1.7 billion yen ($17 million) in 2014, a small part of the country’s overall assistance.

Japan first used development aid for patrol boats in 2007, when it delivered three vessels to Indonesia under a 1.9 billion yen grant for anti-piracy efforts. It has since provided patrol ships to Djibouti, a tiny nation in the Horn of Africa.

Feasibility studies began in March for the possible provision of patrol ships to the Vietnamese coast guard. It’s unclear how much Japan can accelerate approval of the development aid, which typically takes at least two to three years to complete.

"We hear (Vietnam) needs them soon," Suga said, "and naturally we are trying to do so accordingly."

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Associated Press writers Mari Yamaguchi in Tokyo and Jim Gomez in Manila contributed to this story.