Trio in show of unity on North Korean issue

Mrs Clinton's meeting was intended to demonstrate a serious response to recent North Korean actions, including its deadly shelling of a South Korean island last month and its announced expansion of a uranium enrichment capability that the US and others see as a defiant and dangerous step.

"All agree that North Korea's provocative and belligerent behaviour jeopardises peace and stability in Asia," Mrs Clinton said.

Conspicuous in their absence, however, were representatives of the two other countries that have worked with the US, Japan and South Korea on the North Korean problem - China and Russia.

Together with North Korea, they are members of what has become known as the six-party talks.

Asked about China's absence, Mrs Clinton said the meeting was specifically intended to co-ordinate with US treaty allies - Japan and South Korea - rather than convene a larger group.

"We look forward to China playing a vital role in regional diplomacy," she said. "They have a unique relationship with North Korea and we would hope that China would work with us to send a clear, unmistakable message to North Korea that they have to demonstrate a seriousness of purpose."

China, a traditional supporter of North Korea, has called for an emergency session of the so-called six-party talks - with the US, Japan, South Korea, Russia and China in negotiations with North Korea.

But Mrs Clinton made clear that Washington, Tokyo and Seoul viewed a resumption of talks as tantamount to rewarding North Korea for behaving badly.

The North has established a pattern of taking provocative actions, such as testing a nuclear device and launching ballistic missiles, and then seeking through negotiations to gain concessions from the US and its partners.

A part of Mrs Clinton's message was that the Obama administration would not go down that path, although she also reiterated that under the right conditions the US was willing to talk to the North.

"North Korea first needs to take concrete steps to demonstrate a change of behaviour," she said.

In a joint written statement, the three officials condemned North Korea's construction of a new uranium enrichment facility, saying it violated United Nations Security Council resolutions as well as the North's commitments in a September 2005 agreement with the other parties to the six-party talks.

"We would like China to have a clearer stance in giving warning to North Korea" about the consequences of its actions, Mr Kim said.

Mr Kim and Mr Maehara later met Barack Obama's national security adviser Tom Donilon at the White House.

The three expressed common purpose in wanting North Korea to understand that if it stepped back from a nuclear path, "the road to reintegration into the international community will be open, but if it chooses further provocations and threats, it will further isolate itself", National Security Council deputy spokesman Ben Chang said.

On Sunday, Mr Obama called Chinese president Hu Jintao to discuss North Korea, the White House said, and urged him to let North Korea know "its provocations are unacceptable".

The US intervened in support of South Korea when North Korea invaded in June 1950 and is party to an armistice agreement that ended the fighting in July 1953.

Mrs Clinton said she and her Japanese and South Korean counterparts agreed that the North's shelling of Yeonpyeong Island on November 23 was a violation of the armistice.

Meanwhile South Korea's president called for five islands near the disputed sea border with North Korea to be turned into "military fortresses".

Lee Myung-bak instructed his cabinet to gradually push to strengthen fortifications on the islands and to create jobs so residents could continue to live there.