Responding to Newsweek’s question during a press call Monday amid a series of escalations on the Korean Peninsula that included an exchange of warning shots between the armed forces of the rival neighbors, National Security Council Strategic Communications Coordinator John Kirby said that “we have been consistently concerned about North Korean provocations, not just because of the accelerated missile launches, for instance, in the last few weeks.”

“It’s been a consistent concern of ours,” he added, “which is why several months ago we added some intelligence capabilities off the Korean Peninsula to help us get a little bit better insight.”

Yet he reiterated that “the North Koreans could conduct a nuclear test at any time,” while noting that “what’s inside Kim Jong Un’s head is not known to us.”

The move to boost intelligence collection was made as part of a three-point strategy outlined by Kirby, which also included vows “to continue to conduct the bilateral and trilateral exercises with the Japanese and South Koreans,” and “to continue to engage the international community inside the U.N. to try to hold the North accountable through additional economic means.”

Such joint drills, coupled with sanctions against North Korea, have prompted Kim to accuse the U.S. and its allies of pursuing a “hostile” policy against his nation, fueling a spike in military activity to include the testing of tactical nuclear-capable platforms.

Kirby said the Biden administration was well aware of the high stakes-nature of the recent incidents that have raised tensions on the Korean Peninsula, and “that is why not only have we endeavored to improve our military capabilities,” but also have taken steps to bolster security alongside Tokyo and Seoul, whom he noted “are treaty allies” the U.S. is committed to defend.

And while he said the U.S. takes defense commitments “extraordinarily seriously,” he also said the recognition of the grave nature of the situation is “also why we made it clear that we were willing to sit down with Kim Jong Un without preconditions to talk about a denuclearization of the peninsula.”

Thus far, however, Kirby said that “Mr. Kim has proven unwilling to take us up on that offer, and absent that opportunity to sit down and talk about it, we’ve got to make sure that we’re ready to defend against it.”

Asked if such diplomacy would remain on the table in the event of a North Korean nuclear weapons test, Kirby declined to “get into hypotheticals.”

“We said that they could conduct one at any time,” he said. “I will just tell you that the offer stands that we are willing to sit down with them without preconditions.”

It was only after a year of heated nuclear-fueled rhetoric accompanied by North Korean intercontinental ballistic missile (ICBM) launches and a nuclear test that Washington, Seoul and Pyongyang pursued a historic peace process in 2018. But several rounds of leaders-level talks, including two U.S.-North Korea summits, three inter-Korean summits and a trilateral border meeting, failed to reach any lasting peace agreement, setting the stage for tensions to prevail.

Kim would go on to resume missile tests, including ICBMs capable of reaching the U.S. mainland and shorter-range tactical weapons more concerning for Japan and South Korea.

Meanwhile, a growing chorus of South Korean politicians have called on President Yoon Suk-yeol to take tougher measures to respond to North Korea’s ongoing campaign of military displays of might. Some have gone so far as to call for the redeployment of U.S. nuclear weapons to the peninsula 30 years after their withdrawal at the end of the Cold War.

Yoon said Thursday he was “there are diverse opinions across our nation and in the United States regarding extended deterrence, so I am listening to them carefully and looking carefully at various possibilities,” according to the Yonhap News Agency.

And in the wake of Sunday’s exchange of warning shots after Pyongyang and Seoul accused one another of violating their disputed maritime border, a presidential official warned that “North Korea’s continued provocations and claims that try to frame us as being in the wrong harm peace and stability not only on the Korean Peninsula but also in the international community,”

“The more North Korea intensifies its threats,” the official added, “the deeper the isolation of the North Korean government and the more impoverished the North Korean people will become.”

But the North Korean Foreign Ministry defended the nation’s military moves that same day, touting how the Korean People’s Army “recently displayed to the full extent its actual war capacity in response to the grave situation created on the Korean peninsula” through recent weapons tests.

“The military drill of the Korean People’s Army units for the operation of tactical nukes as well as the test-fire of long-range strategic cruise missiles are an exercise of legitimate right to self-defense to root out the cause of tension on the Korean peninsula,” the ministry said, “and to safeguard the peace and stability of the region and achieve genuine international justice.”

The commentary singled out Japan, specifically, over Tokyo’s recent decision to join Seoul in implementing additional sanctions against Pyongyang after over North Korea’s missile tests, one of which overflew the archipelago nation, earlier this month, prompting a nationwide alert.

“Even under the harshest ever sanctions and blockade,” the North Korean Foreign Ministry said, “our country rose to a nuclear power and military power which can annihilate any aggressive forces on earth and reliably safeguard the peace and security on the Korean peninsula and in the region.”