Asian and Western nations have failed to persuade North Korea to resume talks on its nuclear programme at an Asian security forum in Malaysia.
The North Korean delegation refused to hold talks
Officials from 10 countries met to discuss security in North Asia on the fringes of the Asean Regional Forum, but North Korea refused to take part.
Its foreign minister threatened to leave the forum if a joint statement criticised its recent missile tests.
The crisis in the Middle East was also high on the agenda, as was Burma.
The Asean Regional Forum brings together 24 nations, as well as the EU, for one day of talks at the end of the annual Asean (Association of South East Asian Nations) meeting.
This year the forum had been expected to focus on North Korea, amid heightened concern in the wake of its missile tests on 5 July.
Asean: Brunei, Cambodia, Indonesia, Laos, Malaysia, Myanmar, the Philippines, Singapore, Thailand and Vietnam
Six nation talks on N Korea: US, China, N Korea, S Korea, Japan, Russia
Others: Australia, Canada, India, Mongolia, New Zealand, Pakistan, PNG, E Timor
Officials were hoping that delegates from Pyongyang would attend six-party talks on their country's nuclear ambitions on the sidelines of the meeting, but North Korea made it clear this would not happen.
At the forum's opening ceremony, North Korean Foreign Minister Paek Nam-sun threatened to leave the forum if Asean members chose to condemn its missile tests.
"If ARF strongly imposes contents of a joint statement against the will of some countries without consensus, we will think about whether we will remain," he said.
Earlier, North Korean spokesman Jong Song-il said US financial sanctions were "making it impossible for us to go to the six-party talks".
Officials from 10 countries - including the five nations engaged in dialogue with North Korea - later met without the delegation from Pyongyang for security talks on the fringes of the forum.
Ms Rice said it was "unfortunate" that North Korea had declined to hold talks, but said that the US was ready "at any time" to return to the multilateral dialogue.
A chairman's statement released at the end of the talks expressed concern over the tests, which it said could have "adverse repercussions" on stability in the region.
The ongoing situation in the Middle East has also been high on the forum's agenda.
Ms Rice told a news conference that she recognised the "tremendous concern" that governments in the Asia-Pacific region had about the crisis and said she wanted to see "as early an end to the conflict as possible".
But Ms Rice did not give a timetable for her return to the region. "I do think it is important that groundwork be laid so I can make the most of whatever time I can spend there," she said.
Earlier in the week, Asean members called for an immediate ceasefire in Lebanon, contradicting Washington's line.
Adding to the pressure was the presence of Iranian Foreign Minister Manouchehr Mottaki, who held joint talks with the foreign ministers of Malaysia, Indonesia, Bangladesh and Pakistan on the sidelines of the forum.
Outside the convention centre, several hundred anti-US protesters broke through a police cordon to chant slogans criticising its backing of Israel.
The forum also addressed the issue of Burma and its failure to introduce democratic reform.
Earlier in the week, the 10-member Asean grouping issued a statement calling on Rangoon to demonstrate "tangible progress", which international observers criticised as not strong enough.
But Ms Rice called the statement an "important evolution", adding that Asean had spoken "quite clearly" on the need for political reform.
The chairman's statement raised concerns over the pace of reform in Burma, but said the country needed "time and political space to deal with its many and complex challenges".