President Barack Obama and his South Korean counterpart, Park Geun Hye, presented a unified front Tuesday against North Korea's aggressive recent actions, calling on the isolated nation to give up its nuclear program as promised in return for international aid and acceptance.

Speaking at a joint news conference after morning meetings with Park at the White House, Obama said North Korean leader Kim Jong Un's belligerent attempts to divide the United States and South Korea have failed. He also reasserted Washington's commitment to defend Seoul and other allies in the region from the North's aggression.

"Today is further evidence that North Korea has failed again," Obama said. "The days when North Korea could create a crisis and elicit concessions, those days are over."