WASHINGTON (AP) — The Obama administration said Wednesday it wants to make Asia more stable and won't negotiate with North Korea while it keeps critical elements of its nuclear weapons 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 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 that 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.