Attending an Asian security conference, Clinton said China, Japan, Russia and South Korea were all in agreement with Washington on this goal and were in a "strong position" in their dealings with the North Koreans.
Clinton spoke at a news conference Wednesday after bilateral talks with foreign ministers of the four countries.
The Secretary of State arrived at the Association of Southeast Asian Nations, or ASEAN, conference on Wednesday carrying a no-nonsense message that the United States is ready to re-engage with Asia after years of neglect.
Clinton moved right into talks with Asian counterparts gathered for two days of international meetings to discuss North Korea, Myanmar and a range of other regional issues.
She said she would sign the seminal ASEAN Treaty of Amity and Cooperation, a commitment to peacefully resolve regional disputes that already has been signed by more than a dozen countries outside the 10-nation bloc.
"The United States is back," she declared upon arrival in the Thai capital Tuesday.
And in an appearance Wednesday morning on a Thai TV talk show she said, "President Obama and I are giving great importance to this region," suggesting that the administration of former President George W. Bush neglected U.S. interests in Asia.
Evidence of the new U.S. approach, she said, is the fact that her first overseas trip, in February, was to Asia.
"I believe strongly the United States has to be involved in this region," she added. Her main aim in visiting Southeast Asia this time, she said, is to "work hard to try to bring a sense of future possibilities" for partnerships to ensure peace and prosperity.
Clinton was asked whether she thinks the U.S. image abroad has been improving under President Obama. "It certainly feels like it," she said. "There is a great sigh of relief in some places" she has visited this year.
She also said the U.S. has a plan to prevent Iranian domination in the Middle East if it gets the nuclear bomb. "We want Iran to calculate what I think is a fair assessment: that if the United States extends a defense umbrella over the region, if we do even more to develop the military capacity of those (allies) in the Gulf, it is unlikely that Iran will be any stronger or safer."
The U.S. signing of the ASEAN treaty will be by the executive authority of Obama and does not require congressional ratification, said a senior administration official who spoke on condition of anonymity because he was not authorized to discuss the move publicly.
The Bush administration had declined to sign the document, whereas Obama sees it as a symbolic underscoring of the U.S. commitment to Asia.
On Tuesday, Clinton reiterated Obama administration concerns that North Korea, already a threat to the U.S. and its neighbors with its history of illicit sales of missiles and nuclear technology, is now developing ties to Myanmar's military dictatorship.
Clinton held out the possibility of offering North Korea a new set of incentives to return to negotiating a dismantling of its nuclear program if it shows a "willingness to take a different path." But she admitted there is little immediate chance of that.
In her remarks about a possible Myanmar-North Korea connection, Clinton did not refer explicitly to a nuclear link but made clear that the ties are disconcerting.
"We know there are also growing concerns about military cooperation between North Korea and Burma which we take very seriously," she said at a news conference in the Thai capital.
"It would be destabilizing for the region, it would pose a direct threat to Burma's neighbors," she said, adding that as a treaty ally of Thailand, the United States takes the matter seriously.
Later, a senior administration official said that Washington is concerned about the possibility that North Korea could be cooperating with Myanmar on a nuclear weapons program, but he added that U.S. intelligence information on this is incomplete. The official spoke on condition of anonymity because of the sensitive nature of the matter.
The United States, in a joint effort with South Korea, Japan, China and Russia, is attempting to use U.N. sanctions as leverage to compel North Korea to return to the negotiating table over its nuclear program. A major element of the international concern about North Korea is the prospect of nuclear proliferation, which could lead to a nuclear arms race in Asia and beyond.