JERUDONG – Pentagon chief Chuck Hagel warned fellow defence ministers Thursday that a growing number of maritime incidents and tensions in disputed Asian waters increase the risk of a dangerous international confrontation.

Hagel pressed ahead with a second day of talks in Brunei even as the United States prepares for a possible military strike to punish Syria for its alleged use of chemical weapons.

China has faced increasing accusations of bullying tactics in asserting its claim to nearly the whole of the strategic East Sea, parts of which are claimed by several Southeast Asian countries.

Elsewhere, Tokyo and Beijing have played cat and mouse in the East China Sea over disputed islands. Japan earlier this week scrambled fighter jets after a Chinese government plane approached airspace Japan claims as it own.

US Defense Secretary Hagel issued a warning over the simmering tensions at the talks involving defence ministers from the Association of Southeast Asian Nations (ASEAN), Japan, China, South Korea, the United States, Russia, India, Australia and New Zealand.

"Actions at sea to advance territorial claims do not strengthen any party's legal claim. Instead, they increase the risk of confrontation, undermine regional stability, and dim the prospects for diplomacy," Hagel said, according to a prepared text of his remarks.

"All the countries are concerned that a more aggressive pursuit of claims could provoke a conflict," a senior US defence official told reporters, commenting on the ministerial discussions.

Some ministers from the 10-nation ASEAN bloc proposed practical steps to avert conflict, including setting up a hotline between Southeast Asian states and China, measures to avoid collisions and an agreement on "no first use of force", US officials said.

But the main diplomatic effort has centred on calls for a "code of conduct" for the East Sea, a binding set of rules for a waterway believed to hold significant oil and gas deposits.

The United States has backed the idea but China has shown little enthusiasm, though it promised this year to hold future discussions with ASEAN.

Throughout a week-long tour of the region, Hagel has said territorial disagreements should be solved peacefully without "coercion" but has stopped short of directly criticising China.

Hagel met China's defence minister General Chang Wanquan on the sidelines of the meeting in Brunei on Wednesday, after hosting him in Washington earlier this month.

US officials say military relations with Beijing have steadily improved over the past year, with the American and Chinese navies holding joint anti-piracy exercises in the Gulf of Aden.

The high-level American attention on Southeast Asia, including stepped-up US military aid, is part of an effort by Washington to shift its strategic focus to the Asia-Pacific after a decade of wars in Iraq and Afghanistan.

But escalating Syrian tensions have repeatedly intruded on his trip, with the Pentagon chief conferring with European counterparts and White House advisers.

The Syria crisis came up at the gathering on Thursday but was not a focus of the talks, officials said.

During his swing through the region, which included stops in Malaysia and Indonesia and will end with a visit to the Philippines, Hagel has said repeatedly that Washington is committed to its "rebalance" toward the Asia-Pacific despite budget pressures at home and Middle East distractions.

Underscoring Washington's shift, Hagel invited ASEAN members to hold a meeting next year in the United States for the first time, and the defence ministers accepted.