Ambassador Mark Lippert refuted criticisms of U.S. diplomatic approaches to Pyongyang of the last eight years and said the administration spent a great deal of time trying to persuade North Korea to return to the negotiating table, Yonhap reported.
In an exclusive interview with the South Korean news agency's television network this week, Lippert said strategic patience did not lead to North Korea's decision to accelerate nuclear weapons development.
Lippert said there were more active measures taken behind the scenes not covered under the concept of patience, including encouraging North Korea to return to negotiations, pressing for the postponement of nuclear weapons development with economic sanctions, and responding to North Korean threats by building up defense capacity.
Numerous meetings were held at the White House to seek solutions to the North Korea problem, Lippert said, adding that he could not disclose the details of the exchange for reasons of confidentiality.
The U.S. ambassador also told Yonhap that Pyongyang's launch of a long-range rocket in April 2012 was a turning point for the Obama administration.
Two months before the provocation, the United States and North Korea had reached an agreement under the Leap Day deal. Pyongyang had said it was committed to denuclearization and agreed to implement a moratorium on missile launches.
After North Korea violated the agreement, Washington turned to a more sanctions-oriented approach to relations, Lippert said.
Pyongyang's actions have also spoken louder than words for the South Korean government, and Seoul is increasingly skeptical of official North Korean statements.
According to the unification ministry on Friday, Kim Jong Un's upcoming New Year speech will be read mostly as "propaganda," Yonhap reported.
"It is better to avoid giving too much meaning" to the speech, the ministry's spokesman said, pointing out past statements on denuclearization later proved to have little bearing on Pyongyang's policies.