Billing himself America's first "Pacific president", Barack Obama on Saturday said the United States did not seek to "contain" China and promised an engaged US role in charting Asia's future.
Obama also warned he would not be "cowed" by North Korea's nuclear sabre rattling, and repeatedly challenged regional leaders to wean themselves off lucrative US export markets to secure a "balanced" global economic rebound.
The president chose Japan, for half-a-century a bedrock US ally, to deliver his latest major speech framing a new foreign policy, invoking his upbringing in Indonesia and Hawaii to show he shared the region's world view.
"As America's first Pacific president, I promise you that this Pacific nation will strengthen and sustain our leadership in this vitally important part of the world," Obama said on the second day of his debut Asian tour.
He later flew in to Singapore for an Asia-Pacific summit, where he was due to meet regional leaders including China's President Hu Jintao.
His Tokyo remarks signaled yet another break with the foreign policy of ex-president George W. Bush, who is accused by Obama aides of letting US ties with East Asia founder while waging war in Iraq and against global terrorism.
Drawing an enthusiastic welcome from 1,500 people in Tokyo's Suntory concert hall, Obama said he knew many in Asia wondered how Washington viewed China's rise to prominence.
"The United States does not seek to contain China, nor does a deeper relationship with China mean a weakening of our bilateral alliances," Obama said.
"On the contrary, the rise of a strong, prosperous China can be a source of strength for the community of nations."
Just ahead of his first visit to China, Obama warned that he would not waver from raising human rights with Beijing but would do so without "rancor".
But he did not specifically mention Tibet, after criticism that he had avoided Tibet's exiled spiritual leader the Dalai Lama in Washington recently so as not to anger leaders in Beijing.
Some US critics have accused him of downplaying human rights concerns to win Beijing's cooperation on geopolitical headaches like the nuclear ambitions of North Korea and Iran.
In Singapore Saturday, US Secretary of State Hillary Clinton and Chinese Foreign Minister Yang Jiechi met for bilateral talks that China's foreign ministry said covered climate change along with North Korea and Iran.
Many Asian observers believe that the US immersion in bloody wars in Afghanistan and Iraq forced it to take its eye off dynamic Asia, leaving an opening for China to seize a more powerful regional role.
"Even as American troops are engaged in two wars around the world, our commitment to Japan's security and to Asian security is unshakeable," Obama said in his Tokyo speech, against a backdrop of US and Japanese flags.
"It can be seen in our deployments throughout the region -- above all, through our young men and women in uniform."
Obama again called on North Korea to return to six-party talks on ending its nuclear program, but warned Washington would not be "cowed" by threats from Pyongyang, following its detonation of a nuclear device earlier this year.
As he pursues a tentative engagement strategy with Myanmar, Obama called on the junta to release democracy icon Aung San Suu Kyi -- though he stumbled over her name in an apparent sign of fatigue -- in response to US outreach.
On Sunday in Singapore, Obama is due to have an unprecedented meeting with all 10 leaders of the Association of Southeast Asian Nations, including the prime minister of military-run Myanmar.
The meeting will follow the summit of the Asia-Pacific Economic Cooperation (APEC) forum. Obama called on Asian countries to retool their export-led models to support balanced economic growth after the worst global crisis in decades.
"Now that we are on the brink of economic recovery, we must also ensure that it can be sustained," he said. "We cannot follow the same policies that led to such imbalanced growth."
Obama will fly from Singapore to Shanghai Sunday on his debut visit to China, and then travels to Beijing for talks with President Hu. He wraps up his Asian tour in South Korea next week.