U.N. experts said in key sections of the report that North Korea has also evaded sanctions through "targeted" cyber attacks against officials of countries on the U.N. Security Council and on members of its expert panel.

Washington has many "tools in its tool kit" to respond to any such North Korean nuclear missile test, U.S. national security adviser Robert O'Brien said in an interview with ABC's "This Week."

The North's stinging response came after the United States said on Monday it had introduced sanctions on three North Korean officials, including a top aide to North Korean leader Kim Jong Un, for alleged human rights abuses.

The statement released by the Foreign Ministry on Friday evening said North Korea could bring back its "pyongjin" policy of simultaneously advancing its nuclear force and economic development if the United States doesn't change its stance.

President Moon Jae-in intends to more actively perform "the role of a mediator" in various channels between South Korea, the U.S. and North Korea.

North Korea on Wednesday threatened to scrap a historic summit next month between its leader, Kim Jong Un, and U.S. President Donald Trump.

The findings may shed new light on Kim Jong Un's announcement that his country was ceasing its testing program ahead of planned summit meetings with South Korean President Moon Jae-in and U.S. President Donald Trump.

North Korea and the U.S. accused each other of planning nuclear attacks on Tuesday.

The CIA believes that North Korea's next step is to develop the capability to fire multiple missiles at the U.S.

"When it comes to North-South relations, we should lower the military tensions on the Korean Peninsula to create a peaceful environment," Kim said.