From tough new sanctions against North Korea to a sweeping strategy aimed at eliminating nuclear weapons, the U.S. ambassador to the United Nations says President Barack Obama's promise to work with other countries is yielding results.

Nearly a year after becoming the top U.S. diplomat to the global body, Susan Rice said in an interview this week with The Associated Press and AP Television News that challenges remain, though she sees evidence every day "that the world is responding differently and much more openly to the United States of America."

Many nations felt that former president George W. Bush's administration did not have a strong commitment to working with other countries, and they complained that U.S. power as the world's richest nation and a veto-wielding member of the U.N. Security Council was disproportionate.

At the U.N. General Assembly in September, Obama told world leaders the United States would reach out in "a new era of engagement based on mutual interest and mutual respect." And he challenged leaders from the 191 other U.N. member states to share the burden, saying America can't solve the world's problems alone.

Rice, who was Obama's top foreign policy adviser during the presidential campaign, said the United Nations is crucial to carrying out this key foreign policy objective.

"We are at the frontline of president Obama's new era of engagement with the rest of the world," she said. "The change in the nature and tone of our relationships ... is yielding concrete and tangible benefits here at the United Nations _ benefits that advance U.S. interests."

She pointed to the Security Council's approval in June of tough new sanctions against North Korea following its second nuclear test. Veto-wielding council members Russia and China, and sanctions-wary Libya joined in the unanimous vote for the sanctions.

"They have been actively and forcibly implemented by member states all over the world," Rice said. "So North Korea is feeling far greater pressure to halt its nuclear weapons program than it has in the past, and it is indeed giving various indications that it is feeling that pressure and perhaps responding to it." She did not elaborate on how they were responding.

Rice also singled out Obama chairing the Security Council in September _ a first for a U.S. president at a summit of the U.N.'s most powerful body _ when it unanimously adopted a U.S.-sponsored resolution aimed at halting the spread of nuclear weapons and ultimately eliminating them.

She called it "a very significant commitment" by leaders of the 15 council nations which "accelerated and embraced the president's goal of attaining a world without nuclear weapons."