U.S. Secretary of State John Kerry unleashed a harsh criticism Sunday of North Korean leader Kim Jong-un for his "ruthless and reckless" leadership.

Kerry was responding to reports that North Korea executed Jang Song-thaek, the once-powerful uncle of its supreme leader Kim, last week.

"It really reminded me of a video that we saw of Saddam Hussein doing the same thing, having people plucked out of an audience, and people sitting there sweating, and nobody daring to move or do anything," Kerry said during an interview with ABC News in Vietnam.

"It tells us a lot about, first of all, how ruthless and reckless (Kim) is. And it also tells us a lot about how insecure he is, to a certain degree."

Jang, who was reportedly in charge of North Korea’s economic reform measures and its ties with China, was stripped of all of his top posts last week, accused of committing a host of anti-state crimes. A few days later, Pyongyang announced that he was executed after a special military trial.

The news of Jang’s fate shocked the international community, especially as he was apparently a regent for the young North Korean leader, who took over power in December 2011.

Kerry said the communist regime has executed Jang and a significant number of other senior officials, which reflects "a significant amount about the instability, internally of the regime."

"This is the nature of this ruthless, horrendous dictatorship and of his insecurities," said the secretary.

It also underscores the importance of finding a way toward the denuclearization of North Korea, especially in cooperation with China, he added.

In Pyongyang, meanwhile, the North’s state news agency KCNA said Jang’s wife Kim Kyong-hui, who is the leader’s aunt, has been named to an ad-hoc state committee for the funeral of Kim Kuk-thae, a chairman of the Control Commission of the Workers’ Party.

The report suggests she is maintaining her political post despite the execution of her husband.

Speaking to the Associated Press in the North Korean capital, a senior North Korean official said the downfall of Jang won’t affect Pyongyang’s economic policies.

"Even though Jang Song-thaek’s group caused great harm to our economy, there will be no change at all in the economic policy of the Democratic People’s Republic of Korea. It’s just the same as before," Yun Yong-sok, the official at the State Economic Development Committee, was quoted as saying. (Yonhap News)