South Korean President Park Geun-hye told a joint session of Congress on Wednesday that her country will never accept a North Korea armed with nuclear weapons and said the U.S.-South Korean partnership would help remove these weapons from the Korean Peninsula.
"The Republic of Korea will never accept a nuclear-armed North Korea," she said. "Pyongyang's provocation will be met decisively."
North Korea has had nuclear weapons since 2006 and tested them three times, most recently this year.
Park said she signed a new declaration with President Obama this week aimed at achieving peace on the Korean Peninsula, cooperation in Asia, and prosperity around the world. She said ensuring peace on the Peninsula will be difficult given Pyongyang's recent provocations.
But Park said close cooperation with the United States will help ensure the right result.
"Korea's economic fundamentals are strong. Its government is equal to the task, and it is backed by the might of our alliance. So long as this continues, you may rest assured: No North Korean provocation can succeed," she said to a standing ovation.
Park also won applause for saying the international community must break the cycle of giving North Korea time to advance its nuclear weapons program.
"The pattern is all too familiar, and badly misguided," she said. "North Korea provokes a crisis, the international community imposes a certain period of sanctions. Later, it tries to patch this up by offering concessions and rewards.
"Meanwhile, Pyongyang uses that time to advance its nuclear capabilities, and uncertainty prevails. It is time to put an end to this vicious circle."
Park added that Pyongyang will find it cannot pursue a nuclear arsenal and economic development at the same time. "We know these are incompatible. You cannot have your cake and eat it too," she said to laughter.
"The leadership of Pyongyang must make no mistake. Security does not come from nuclear weapons. Security comes from when people's lives are pursued. It comes from when people are free to pursue happiness."
Park used her speech to Congress to call for a revised civil nuclear agreement that would allow South Korea to pursue peaceful uses for nuclear power. Secretary of State John Kerry has said the U.S. is looking for a way to reach agreement on this sensitive issue.
"We have a long record of close cooperation on this issue, and we are committed to finding a workable, expeditious way forward," Kerry has said.
"Such an accord will bring huge benefits to industry in both of our countries," Park told Congress.
She also welcomed the implementation of the U.S.-Korean free trade agreement and called on Congress to approve legislation expanding visas for Korean professionals to work in the United States.
"We can do even more if the bill on visa quotas for Korean professionals is passed in this Congress," she said. "Both our economies will benefit, for it would help create many more jobs."
Park used the start of her speech to thank the United States for its involvement in the Korean War, and she thanked the four members of Congress who served in that war: Reps. John Conyers (D-Mich.), Charles Rangel (D-N.Y.), Sam Johnson (R-Texas) and Howard Coble (R-N.C.).