TOKYO (REUTERS) - US Secretary of State John Kerry defended the re-orientation of US foreign policy towards Asia on Monday as he ended a trip to the region dominated by concerns about North Korea's nuclear programmes.
The "rebalancing" of the United States towards Asia has caused unease in Beijing, which has tended to focus on the military dimensions of the strategy and to view it as a way to contain China's rise.
On the final leg of a 10-day trip that included stops in Seoul and Beijing, Mr Kerry sought to assuage Chinese concerns even as he offered reassurance to US allies such as Japan and North Korea that the United States wasn't going anywhere.
"Some people might be sceptical of America's commitment to this region," Mr Kerry told students at the Tokyo Institute of Technology.
"My commitment to you is that as a Pacific nation that takes our Pacific partnership seriously, we will continue to build on our active and enduring presence."
The United States has beefed up its military presence in the region in recent weeks, deploying two missile defence systems following repeated North Korean threats to attack the United States and its allies.
The North increased its menacing language after the UN Security Council imposed new sanctions in response to its latest nuclear arms test - its third - in February. Speculation has mounted of a new missile launch or nuclear test.
Mr Kerry has stressed his interest in a diplomatic solution.
"The United States remains open to authentic and credible negotiations on denuclearisation, but the burden is on Pyongyang," he said.
"North Korea must take meaningful steps to show that it will honour commitments it has already made, and it has to observe laws and the norms of international behaviour."
On Sunday evening, however, Mr Kerry appeared to open the door to talking without requiring the North to take denuclearisation steps in advance.
Beijing, he said, could be an intermediary.
"If the Chinese came to us and said, 'look, here's what we've got cooking and so forth,' I'm not going to tell you that I'm shutting the door today to something that's logical and that might have a chance of success," he said.
While signaling US support for its Asian allies, Mr Kerry also said he did not want territorial disputes between Japan and China to jeopardise the region's security and prosperity.
"It is time also to put long-festering territorial pursuits behind us," he said.
"The stakes are far too high and the global economy is too fragile for anyone to allow these inherited problems to divide the region and to inflame it."
Tensions between the two nations soared last year over rival claims to a crop of islands in the East China Sea.