'Time Running Out' to Avoid War with North Korea, U.S. Official Says

National security adviser H.R. McMaster with President Donald Trump. BULLIT MARQUEZ/AFP/Getty Images

Right now is the "last, best chance to avoid conflict" with North Korea and "time is running out," President Donald Trump's national security adviser said on Tuesday.

H.R. McMaster, speaking at an event for the British think tank Policy Exchange, described dire circumstances as the administration tries to counter North Korea's developing nuclear weapons program.

He was previewing the new National Security Strategy, a document put out by each administration that shapes how it approaches foreign policy and national security issues during its tenure. Trump will unveil the full document on Monday.

McMaster's remarks come after North Korea demonstrated a missile last month that, experts say, puts the continental U.S. in range. Trump and North Korean leader Kim Jong Un have also traded verbal barbs, with Trump calling Kim "Rocket Man" and Korean government outlets referring to Trump as a "dotard." Those threats and the advances in North Korea's nuclear program have heightened tensions on the Korean Peninsula and pushed the two sides toward what experts say would be a horrific war.

The National Security Strategy document includes language about how the administration is dealing with North Korea. McMaster said that policy is focused on the "denuclearization of the Korean Peninsula," not ousting Kim Jong Un. That includes potential action against companies that illegally do business with North Korea, along with continued pressure on China to help curb North Korea's nuclear tests.

"Now it's time for all nations to do more," McMaster said.

North Korean leader Kim Jong Un inspects a hotel. AFP/Getty Images

He was joined onstage at the event by Britain's national security adviser, Mark Sedwill, who said that North Korea cannot be simply normalized as part of a solution.

"North Korea's government is dependent on isolation," he said. "Those who talk about reintegrating North Korea miss the point of that regime."

McMaster said that the new national security strategy will broadly focus on "competition," in addition to discussing threats from Russia, Iran, North Korea and militant groups. That means bolstering the U.S. military to face off against countries with strong militaries, like China and Russia, while also developing new technologies in areas like cyberwarfare.

Another section of the strategy will focus on "cooperation with reciprocity," a phrase meant to coax U.S. allies to spend more on defense, a critical component of Trump's campaign rhetoric on national security.

On Iran, the strategy will focus on issues "outside of the nuclear deal," McMaster said, while criticizing President Barack Obama's administration for its focus on the agreement, which is broadly disliked by Republicans. The administration has consistently complained about Iran's support for militant groups across the Middle East.

That support was not expressly forbidden in the nuclear deal, which was more narrowly focused on preventing the development of an Iranian nuclear weapon.