National Security Adviser H.R. McMaster slammed predecessor Susan Rice for writing the U.S. could potentially "tolerate nuclear weapons in North Korea," saying Sunday that "she's not right."

Rice, who served as National Security Adviser during the second term of the Obama administration, wrote in the New York Times that President Donald Trump's "bluster" was contributing to global anxiety.

"History shows that we can, if we must, tolerate nuclear weapons in North Korea — the same way we tolerated the far greater threat of thousands of Soviet nuclear weapons during the Cold War," she wrote. "It will require being pragmatic."

"Is she right?" ABC host George Stephanopoulos asked after reading out that section.

"No, she's not right, and I think the reason she's not right is that the classical deterrence theory, how does that apply to a regime like the regime in North Korea?" McMaster asked. "A regime that engages in unspeakable brutality against its own people. A regime that poses a continuous threat to its neighbors in the region and now may pose a direct threat to the United States with weapons of mass destruction."

Trump issued a series of mounting threats toward North Korea last week in response to further belligerent behavior from the rogue nuclear state. Trump at one point said North Korea could expect "fire and fury" if it continued threatening the U.S. and its allies.

On Friday, Trump said Kim Jong-un would "regret it fast" if he attacked the U.S. Pacific territory of Guam.

A U.S.-led effort brought about a United Nations Security Council resolution on Aug. 5 that imposed tough sanctions against North Korea for its continued intercontinental ballistic missile testing and flouting of U.N. resolutions.

The CIA and other top intelligence agencies have agreed that North Korea has successfully miniaturized a nuclear weapon to place on a ballistic missile.