|Visiting Australia, Obama has made it known that the Asia-Pacific region is 'vital' to US interests [GALLO/GETTY]
Barack Obama has indicated a significant shift in US policy vis-a-vis Asia, pledging he would not let his country's budget crisis compromise its strategic vision and military presence in the region.
His commitment came a day after the US said it would deploy up to 2,500 troops to northern Australia and tighten air force co-operation, causing concern in China, whose rapid rise is reorienting Asia's strategic balance.
In a message aimed both at a dynamic region he sees as key to the US economic future and politicians at home, Obama told the Australian parliament on Thursday the Asia-Pacific was too vital to fall prey to US penny-pinching.
"As the United States puts our fiscal house in order, we are reducing our spending," Obama said, cautioning that reductions in funding for the US military machine were inevitable after years of huge spending in Iraq and Afghanistan.
"Here is what this region must know. As we end today's wars, I have directed my national security team to make our presence and missions in the Asia-Pacific a top priority.
"As a result, reductions in US defence spending will not - I repeat, will not - come at the expense of the Asia-Pacific.
"The United States is a Pacific power, and we are here to stay."
Obama's promise came at an inopportune moment, however, as by coincidence the US national debt passed $15tn for the first time hours before he spoke, prompting Republicans to criticise the president for profligate spending.
Ties with China
During the speech, Obama addressed the sensitive issue of ties with China, pressed for more reform in Myanmar and said North Korea would pay a heavy price for the proliferation of nuclear or other materials to states or individuals.
"The US will continue our effort to build a cooperative relationship with China," Obama said on a tour which has exposed divisions between Washington and Beijing-.
"All of our nations have a profound interest in the rise of a peaceful and prosperous China - and that is why the US welcomes it," he said.
"We will do this, even as we continue to speak candidly with Beijing about the importance of upholding international norms and respecting the universal human rights of the Chinese people."
Al Jazeera reports on the proposed new US-Australian security agreement
Obama's comments on funding represent a crucial moment in US policy towards a region beset by territorial disputes, containing trade routes vital to US prosperity, and which is transfixed by the rise of China.
He gave his commitment on the latest leg of a Pacific tour which is meant to underscore that the US will remain a crucial player in Asia-Pacific security.
After Australia, Obama heads to East Asian summit talks in Indonesia.
"We will preserve our unique ability to project power and deter threats to peace," Obama said.
"And we will constantly strengthen our capabilities to meet the needs of the 21st century. Our enduring interests in the region demand our enduring presence in this region."
Al Jazeera's Melissa Chan, reported from Beijing, said that the Chinese had reacted strongly to Obama's visit.
"For the Chinese, the reaction is the sense that they're being encircled," she said, noting the existing US-Japan military relationship.
The People's Daily, the Chinese newspaper that is the organ of the ruling Communist Party, was clear in its opposition to reinforced US-Australia security ties, she said..
"Australia surely cannot play China for a fool. It is impossible for China to remain detached no matter what Australia does to undermine its security," the paper said.
For his part, Obama believes that the Pacific rim, worth trillions in dollars in trade to the US, is vital to America's economic future, and will produce jobs and prosperity for decades to come.
In his speech, Obama surveyed US policy towards Asia, which has evolved in three years and three trips to the region that he has taken as president.
"Here, we see the future," he said, pledging his administration would "play a larger and long-term role in shaping this region and its future".
"As the world's fastest-growing region - and home to more than half the global economy - Asia is critical to achieving my highest priority: creating jobs and opportunity for the American people."
Before his address to parliament, Obama laid a wreath at the Australian War Memorial and he later departed for Darwin, where the new deployment will be based.
In the tropical northern outpost, he will visit the memorial of the USS Peary, which honours the 89 men killed when the warship was bombed by the Japanese during World War II raids on the port.