WASHINGTON (AP) - The Obama administration said Wednesday it wants to make Asia more stable and is open to negotiations with North Korea to tackle the threat posed by its nuclear weapons program _ but not while the North keeps critical elements of its atomic program running.
National Security Adviser Susan Rice also warned Pyongyang could face tougher sanctions if it acts provocatively.
She made the comments Wednesday in an Asia policy speech where she underscored U.S. commitment to the region and announced President Barack Obama would visit the region in April.
Political discord in Washington that caused a two-week partial government shutdown and brought the U.S. close to a debt default prompted Obama to cancel a four-nation trip to Asia in October and added to perceptions that his administration's foreign policy rebalance to the region is running out of stream.
Rice did not specify where Obama would travel. In October, he had been due to attend regional summits to Indonesia and Brunei, and also visit Malaysia and the Philippines.
Speaking at Georgetown University in Washington, Rice stressed the importance of cooperating with China, including on confronting the threat posed by North Korea, which relies heavily on its economic ties with China.
North Korea conducted an atomic test in February and this summer reportedly restarted a plutonium reactor. But with prodding from Beijing, the North has since said it wants to resume, without preconditions, international aid-for-disarmament negotiations it pulled out of five years ago.
Rice said rolling back the threat posed by North Korea is a priority, and the U.S. is open to credible negotiations that get at the entirety of the North's nuclear program. But she added that for Pyongyang to engage in dialogue while keeping critical elements of the program running is unacceptable.
"We will continue to join with international partners, especially China, to increase pressure on North Korea to denuclearize," Rice said, warning the U.S. would "maintain and expand, as necessary," bilateral and multilateral sanctions.
"There will continue to be significant costs to future provocations," she said.
Rice emphasized the importance of regional security cooperation with U.S. allies including Australia, which was holding annual talks on defense and other issues with the U.S. on Wednesday. Afterward, U.S. Defense Secretary Chuck Hagel announced that the number of U.S. Marines deployed in northern Australia there would rise to 1,100 next year.
Obama administration is seeking to rebalance America's military presence toward Asia from the Mideast _ widely viewed as a response to China's military buildup. A report to the U.S. Congress released Wednesday predicted Beijing could possess the largest fleet of modern submarine and combatant ships in the western Pacific by 2020.
Rice did not directly address those concerns in her speech, but she referred to maritime disputes that China has with neighbors as posing a "growing threat to regional peace and security."
She said America's military engagement with China is improving, and that greater transparency could help manage "the realities of mistrust and competition" between the two powers.
She said the U.S. also seeks to elevate its economic relationship with China, and welcomed plans of market-based reform announced by the nation's ruling communist party last week. She said if realized, the reforms could go a long way toward leveling the playing field for foreign and private investors.
Rice said China, like any nation, would be welcome to join a trans-Pacific trade pact the U.S. is negotiating with Japan and 10 other countries but it must be willing to live up to the pact's high standards.
The Trans-Pacific Partnership is meant to reduce tariffs and regulatory barriers, as well as unfair practices by state-owned enterprises, which remain a dominant in key sectors of China's economy.
The U.S. wants to negotiate the agreement by year's end, but analysts say that will be very tough to pull off.
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