WASHINGTON (AFP) - US Secretary of State Condoleezza Rice saw her revamped nuclear diplomacy stall on Iran but stay the pace on North Korea as she prepared to fly to the Middle East and Asia late Sunday.

In Abu Dhabi on Monday, Rice and Gulf Arab allies were to get a first-person account from her number-three envoy about his unprecedented but apparently fruitless participation in talks Saturday with the Iranians in Geneva.

With far more to show for her diplomacy on North Korea , Rice is due Wednesday and Thursday to visit Singapore and meet her North Korean counterpart at what could be the informal launch of the last stage of its denuclearization.

Iran gave no sign it would comply with international calls to halt uranium enrichment, even though Undersecretary of State William Burns went to Geneva in a shift from past US policy of rejecting meetings with Iran until it yields.

Washington said it sent Burns to Geneva to show Washington is "serious" about backing diplomatic efforts to end a long standoff that has raised fears of Israeli or even US military strikes against Iran.

The diplomacy involves the five permanent UN Security Council members -- the United States, China, Russia, Britain, and France -- plus Germany. The West charges Iran with seeking nuclear weapons -- charges denied by Iran.

US officials say Burns was to brief Rice in person as well as United Arab Emirates leaders and possibly other Sunni Gulf Arab allies who are concerned about both non-Arab Shiite Iran's nuclear ambitions and the risk of war.

EU foreign policy chief Javier Solana, leading efforts for Iran to accept new incentives to stop enrichment, said in Geneva "it was a constructive meeting, but still we didn't get the answer to our questions."

The Iranians were expected to respond to the latest incentives within two weeks, Solana said.

Iran's top nuclear negotiator Saeed Jalili said after Saturday's talks that "there are points in common and points that are not in common. We have agreed to discuss this."

Rice's spokesman Sean McCormack hinted in Washington that Iran could face more punitive measures on top of the three rounds of UN Security Council sanctions if it did not change course.

"We hope the Iranian people understand that their leaders need to make a choice between cooperation, which would bring benefits to all, and confrontation, which can only lead to further isolation," McCormack warned.

Analysts said the US diplomatic move on Iran carried echoes of its pragmatic shift in 2006 toward North Korea, which produced a landmark nuclear disarmament deal last year.

And last month North Korea paved the way to dismantling all its nuclear programs when it gave a partial accounting of its atomic programs and promised to finish disabling its plutonium reactor by October.

Rice will follow up with those efforts in Singapore Thursday on the sidelines of the Association of Southeast Asian Nations (ASEAN) Regional Forum, a top security gathering.

She is to meet for the first time North Korean Foreign Minister Pak Ui-chun in an informal meeting of the top diplomats of the six-country denuclearization talks that also include South Korea, China, Japan and Russia.

"The process is moving in the right direction based on action for action," McCormack said of North Korea's progress. At the Singapore meeting, he said, "Our message will be, let's move this process forward."

The 27-member ARF, which includes nations from Asia as well as the European Union and the United States, meets at the end of a meeting of the 10-member ASEAN.

Pakistan is in ARF, and Washington could discuss its growing concerns about Islamic militants on the Pakistani border with Afghanistan.

At ASEAN, Rice is expected to criticize Myanmar's human rights record and push the country to adopt democratic and political reforms, US officials said.

Myanmar could face a demand from its neighbours to release all political prisoners, a proposal made by the bloc's senior officials which their foreign ministers must decide whether to endorse.

If approved, the measure would signal a toughening of ASEAN's stance that would be welcomed by Western governments.

Rice is also due to visit Perth, Australia and Auckland, New Zealand as well as make stops in Apia, Samoa and Hawaii, the State Department has said.

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