In a direct challenge to North Korean leaders, President Barack Obama implored them ``to have the courage to pursue peace'' while warning of the wrath of world if they don't. Failure, he said, would mean a future without dignity, respect or hope for its people.

Obama stood by his pledge for a globe without nuclear weapons, declaring the United States has more than it needs and can cut its arsenal without weakening its security or that of its allies.

In unusually personal terms, Obama said he spoke of his wish for further nuclear reductions as the president of the only nation ever to use nuclear weapons, as a commander whose country's nuclear codes are never far from his side, and as a protective father eager to erase the threat of nuclear annihilation.

Obama spoke most directly to North Korea's leaders, saying the internationally isolated country needs to change its ways because continuing down the same path will lead to ``more broken dreams'' and ``more isolation.''

Speaking at Hankuk University in the midst of an international nuclear summit, Obama said that the international community has made progress in reducing the threat of nuclear material but says ``we're under no illusions.''

``Even as we have more work to do, we can already say with confidence that we have more nuclear weapons than we need,'' he said. ``I firmly believe that we can ensure the security of the United States and our allies, maintain a strong deterrent against any threat, and still pursue further reductions in our nuclear arsenal.'' (AP)