US Defense Secretary Ashton Carter said he would visit an American aircraft carrier in the South China Sea on Thursday as US-Chinese tensions over the waterway escalate.

Speaking after a regional summit Wednesday, Carter said he would fly out to the nuclear-powered USS Theodore Roosevelt, which "is conducting routine operations while transiting the South China Sea".

Carter's visit could increase discord between Washington and Beijing over Chinese claims to virtually the entire Sea, and its attempts to reinforce those claims by turning reefs and tiny islets into full-fledged islands through reclamation.

Last week Washington pressed its right to freedom of navigation by sending the guided missile destroyer USS Lassen to within 12 nautical miles of at least one of the artificial islets in the Spratlys chain, angering China.

Earlier Wednesday Carter attended an Asia-Pacific defence ministers' meeting in Malaysia that ended on a sour note as the United States and China butted heads over whether a final joint statement should mention the South China Sea.

"We could not reach a consensus on a joint declaration," Malaysian Defence Minister Hishammuddin Hussein told reporters.

Carter said he had gone into the summit with "no expectation" there would be an agreement.

That illustrates "the level of concern that was reflected in the conversation about activities in the South China Sea", he said, noting that all countries he met with raised the issue.

"It was a persistent topic," he said. "To me, that says that's something we all need to pay attention to."

But both China and the United States pointed the finger at each other.

The US side said several Southeast Asian defence ministers opposed China's demand that the South China Sea be left out of any statement.

A US official said the United States felt that "no statement is better than one that avoids the important issue of China's reclamation and militarisation in the South China Sea".

China's claims to almost all the waterway are widely disputed.

Malaysia, the Philippines, Vietnam, Brunei and Taiwan also have various claims, some overlapping, though none are as extensive as Beijing's.

"We urge all claimants to permanently halt land reclamation, stop the construction of new facilities and cease further militarisation of disputed maritime features," Carter said.

The Sea has long been viewed as a potential flashpoint, and the Chinese island-building has heightened fears of conflict.

The work includes runways and other large-scale development, making the islands potentially capable of hosting military personnel and hardware.

The US official stressed that the Roosevelt would be far from any of the reclaimed Chinese "islands" at the time of Carter's visit, and the ship was not conducting the sort of freedom of navigation cruise performed by the USS Lassen.

- 'Bottom line' warning -

Carter will be joined on the visit by Hishammuddin. They are expected to spend a couple of hours onboard.

"The Teddy Roosevelt's presence there, and our visit, is a symbol of our commitment to our 'rebalance' and the importance of the Asia-Pacific for the United States," Carter said, referring to America's strategic shift to the region.

Wednesday's annual dialogue in Malaysia included defence ministers from the 10-country Association of Southeast Asian Nations (ASEAN) and several regional partners such as Carter and China's Defence Minister Chang Wanquan.

China's state-run Xinhua news agency quoted the country's defence ministry expressing "regret" over the failure to agree on a final text.

It said agreement had been reached with ASEAN countries on the wording but "individual countries outside the region" -- an apparent reference to the United States -- attempted to "forcefully add" new content.

Carter told Chang in a bilateral meeting late Tuesday that the United States would continue sailing in waters China claims.

Chang responded by warning that there was a "bottom line" below which Beijing would act to defend the islets, according to a US account of the talks, but the US delegation told reporters this would not deter future warship sailings.

China and its allies in ASEAN have previously opposed declarations at the grouping's meetings expressing concern at Beijing's maritime conduct.

But recent ASEAN declarations have increasingly made clear its worries over China's actions.