BALI, Indonesia -- Tentative steps by North and South Korea to repair relations are not enough to warrant renewed multination nuclear disarmament talks, the U.S. said Saturday at an Asian security conference where it also took a tough line on resolving tensions in the South China Sea.
Declaring the United States a "resident power" with vital strategic interests throughout the Asia-Pacific, U.S. Secretary of State Hillary Rodham Clinton said North Korea must do more to improve ties with the South before Washington will consider resuming talks aimed at getting Pyongyang to abandon nuclear weapons in return for concessions.
In addition, Clinton laid out specific guidelines for the peaceful settlement of competing territorial claims in the South China Sea, saying recent threats and flare-ups are endangering the security that has driven the region's economic growth and prosperity.
The ASEAN Regional Forum that brought together 27 nations from the U.S., Asia and Europe opened with a buzz early Saturday, with South Korea's foreign minister, Kim Sung-hwan, and the North's Pak Ui Chun chatting and walking casually into the conference hall together.
A day before, their top nuclear negotiators met for the first time since disarmament talks collapsed in 2008 when Pyongyang walked out to protest international criticism of a prohibited long-range rocket launch.
Clinton told diplomats she was encouraged at the signs of progress.
"But we remain firm that in order for six-party talks to resume, North Korea must take steps to improve North-South relations," she said. "North Korea continues to present a critical proliferation challenge to the international community and to threaten regional stability with its provocative actions."
Since the last round of talks, North Korea has conducted a second nuclear test and revealed a uranium enrichment facility that could give it another way to make atomic bombs. Recent threats against Seoul's conservative government include a vow to retaliate over soldiers' use of pictures of the ruling North Korean family for target practice.
Ahead of Saturday's conference, China and its Southeast Asian neighbors agreed to a preliminary plan to resolve territorial disputes in the potentially resource-rich South China Sea.
China says it has historical claims to the entire, potentially resource-rich sea -- of tremendous strategic importance to everyone, including Washington, because one-third of the world's shipping transits through it.
It's believed to have vast oil and gas reserves beneath the seabed and is teeming with fish.
The loudest protests have come from the Philippines and Vietnam, saying increasingly assertive Chinese ships have interfered with their oil-exploration efforts or bullied crews, something Beijing denies. Taiwan, Malaysia and Brunei have also laid claim to overlapping areas.
Philippine Foreign Secretary Albert del Rosario said there have been at least seven aggressive intrusions this year in waters that were 85 nautical miles from the nearest island in his country and 600 nautical miles from China's coast.
"If Philippine sovereign rights can be denigrated" by China's baseless historical claims to the South China Sea, he said, "many countries should begin to contemplate the potential threat to navigation."
A Chinese spokesman for the delegation, Liu Weimin, told the meeting the allegations were groundless, according to Xinhua news agency.
"It's a fact that the South China Sea situation has been always peaceful and stable," it quoted Foreign Minister Yang Jiechi as saying. He reiterated Beijing's position that the "dispute should be resolved directly between two related countries, peacefully through friendly discussion."
Clinton urged all parties to show restraint and to comply with international law "and resolve their disputes through peaceful means." It's vital, she said, that they work together.
As a starting point, the Obama administration wants all nations to map out their territory in terms consistent with customary international law, a senior U.S. official said on condition he not be named, adding that many of the claims seem to be "exaggerated."
South Korean Foreign Minister Kim, meanwhile, said his North Korean counterpart, Pak, "expressed considerable sympathy" when told the two sides needed to lead the disarmament talks, Yonhap news agency quoted Kim as saying Saturday after the ARF meeting.
He provided no details about their brief face-to-face, saying "it's not appropriate to make that public without asking the other party for prior consent," especially at a sensitive time of trust building.
North Korea's state news agency, although covering the event, omitted mention of talks between the two Koreas' nuclear envoys or between Pak and Kim.
North Korea stands to get badly needed aid and other concessions if it returns to the negotiating table and has indicated in recent months that it may be ready. Pyongyang's main ally, China, also has been pressing for a speedy resumption of the talks, but others involved in the talks are more cautious.
Diplomats have long experience with seeing North Korea engage in negotiations and agree to concessions before ultimately putting up roadblocks that prevent real progress.
Clinton and the foreign ministers of Japan and South Korea met on the sidelines of the security forum to assess the situation and plot a way forward.
Japan's foreign minister, Takeaki Matsumoto, said he hoped continuing solidarity between the three allies would help to further deter provocative actions by the North.
The political situation in Myanmar was also on the agenda Saturday.
Clinton said the military-dominated country has reached a "critical juncture."
Myanmar's new civilian government, which took over late last year after a half-century of military rule, needs to make "concrete, measurable progress" in bringing about democratic reforms if it wants to win the confidence of the international community, she said.
That includes releasing more than 2,000 political prisoners and holding meaningful dialogue with its political opponents.