Updated with comments from a Chinese official and the US cCongressional delegation.

SINGAPORE — In a major address Saturday, US Secretary of Defense Ash Carter once again asserted America's right of transit in the Pacific while continuing to single out China as a bad actor in the region.

Carter used his keynote opening the IISS Shangri-La Dialogue conference to paint China as a threat to a regional balance that he says has benefited all parties.

In particular, he prodded China on its continued rapid reclamation efforts, which have resulted in 2,000 acres of land China claims as sovereign territory that the US refuses to recognize.

"China is out of step with both the international rules and norms that underscore the Asia-Pacific's security architecture, and the regional consensus that favors diplomacy and opposes coercion," the secretary said in prepared remarks.

He acknowledged that others in the region have developed reclaimed outposts, including several US partners, but characterized China's actions as above and beyond anything seen before.

"It's true that almost all the nations that claim parts of the South China Sea have developed outposts over the years … of differing scope and degree. In the Spratly Islands, Vietnam has 48 outposts; the Philippines, eight; Malaysia, five; and Taiwan, one.

"Yet, one country has gone much farther and much faster than any other," he said. "And that's China."

Carter also asserted America's claim to the Pacific, stating "the United States has every right to be involved and be concerned" about the region.

The speech widely echoed comments made last week at Pearl Harbor in Hawaii, where he pledged that "the United States will fly, sail and operate wherever international law allows" — a line he repeated verbatim during Saturday's event.

That is a clear shot at China, which believes the reclaimed land is sovereign territory under international law.

"All countries should have the right to freedom of navigation and overflight so global commerce can continue unimpeded," Carter said Saturday. "And all nations should be able to make their own security and economic choices free from coercion.

"These are the rights of all nations. They are not abstractions, nor are they subject to the whims of any one country. They are not privileges to be granted or withdrawn by any country."

While the speech notably poked China, Carter also struck a diplomatic tone, emphasizing a desire to strengthen regional ties.

To that end, he highlighted humanitarian and economic efforts that have successfully drawn together Asian nations in recent years. The speech also mentioned how important it is to maintain military-to-military communications and cooperation with China.

"That's how we reach the future a stronger security architecture affords," Carter said, "a future where everyone continues to rise."

But even those cooperative comments carried a clear message to China, with an emphasis on building up the maritime security capabilities of nations like Vietnam, Malaysia and the Philippines — all nations that are increasingly wary of a rising Chinese presence in the South China Sea.

Carter, and the Obama administration as a whole, is attempting to walk a fine line on China. On the one hand, they want to reassure regional partners and assert America's place as a Pacific power. On the other, they have to be careful not to push China too hard and trigger an escalation of tensions.

Analysts say Carter's comments on his Asian swing have reflected that dichotomy.

Zhuang Jianzhong, vice director of the Center for National Strategy Studies at Shanghai Jiao Tong University, described Carter's Hawaii speech as "quite aggressive," but believes that is largely for show.

"Carter says something harsh for his domestic audience and another for his allies and friends," Jianzhong said. "The rhetoric is one thing and actual action is another thing. Both sides have to think twice before taking any meaningful actions."

But Ching Chang, a research fellow at Taiwan's ROC Society for Strategic Studies, warned that consistency is important in communication between the two sides, and Carter waving around both the proverbial carrot and stick could backfire.

Doing so could undermine US credibility, or as Chang put it, simply make the US look like a bully.

Ng Eng Hen, Singaporean Minister of Defence, called for patience as discussions between all sides continue.

"Let's recognize it will be difficult, [as] these dispute claims have gone on for a long time," Ng said. "We ought to be patient about this, because the alternative is much worse."

Chinese Reaction

That communication challenge became evident during a question and answer session after Carter's remarks.

The sSecretary avoided answering directly on questions about China's view of the region and what the US is willing to do if its rival continues to push into the region, instead relying on general statements to lines of inquiry from the audience.

The room began to buzz with when the moderator called upon a representative from the Chinese People's Liberation Army, identified as "Senior Colonel Zhao."

Zhao predictably took issue with Carter's characterization of his nation's actions, beginning with a small lecture on how China views the situation.

"Over the past decades, the region has been peaceful and stable, just because of China's great restraint," he said. "So I think China's activities are… legitimate, reasonable and justified."

Zhao then asked how the "harsh criticisms" coming from the US "help to resolve the disputes" in the South China Sea.

Carter, who clearly expected such a question from the audience, noted that China's recent reclamation efforts are "unprecedented" in scale but reiterated that the US would like to see all claimants of the South China Sea to halt reclamation programs.

But he did not step back from his comments on China's actions, instead reiterating a talking point from earlier in the week that the US has not changed its policy towards the region.

"The US has been flying and sailing in the South China Sea for decades and decades and decades, and we don't intend to change that in any way," Carter said. "That is not a new fact."

Senate Input

A US cCongressional delegation made up of five members of the Senate Armed Services Committee held a press conference after Carter's speech, during which the bipartisan group said that Congress backs the Obama administration's interest in the South China Sea.

Committee chair Sen. John McCain, R-Ariz., called Carter's remarks "very important" but stressed that now they must be "translated into action."

"We are not trying to thwart china's peaceful development. We certainly do not seek conflict with China," McCain said. "And we do not believe Asian countries should be forced between good relations with China and good relations with America – that is a false choice."

However, he called Chinese actions in the South China Sea "a concerted effort to change the status quo in the region unilaterally, coercively, and with blatant disregard of the views of its neighbors. We need to recognize this reality that China will likely continue... with its activities unless and until it perceives that the cost of doing so outweigh the benefits."

Sen Jack Reed, D-R.I. and the ranking Democrat member on the SASC, followed up on McCain's remarks by claiming China's "unilateral and aggressive behavior is not only detrimental to the region but also detrimental to China," while Sen. Mazie Hirono, D-HI, called China's actions "provocative."

Wendell Minnick in Singapore contributed to this report.

Twitter: @AaronMehta