"Diplomacy is always our goal. Our goal is to reduce the risk of escalation. But, to date, we have not received any response," Psaki said, noting that the outreach "follows over a year without active dialogue with North Korea, despite multiple attempts by the US to engage."

"That's just a non-starter for the North Koreans," said Jeffrey Lewis of the Middlebury Institute of International Studies.

'Denuclearization is a non-starter'

"Denuclearization is a non-starter," said Vipin Narang, an associate professor of political science at the Massachusetts Institute of Technology, who added that "every time we use that phrase it's a five-yard penalty, because the North Koreans never agreed to it."

North Koreans see several reasons why they should not denuclearize based on recent history, including situations in Iraq, Libya and more recently Iran. Leaders in Iraq and Libya were toppled after relinquishing their nuclear programs under US pressure, while Iran entered a deal with the US only to have the Trump administration withdraw, impose crippling economic sanctions and then assassinate the country's leading general and nuclear scientist.

Frank Aum, the senior expert on North Korea at the US Institute of Peace, noted that "it's fine to hold to the long term goal of denuclearization, complete denuclearization for North Korea, but I think the way you message that is going to be very important."

"It has to be nuanced because you can't just say, you know, we want to have talks, and the talks are going to be about North Korea's complete denuclearization, because that sounds very one sided," he told CNN. "It would have to be long term and not the Libya model of complete denuclearization upfront before we give them anything they want."

In 2018, following a summit in Singapore between then-President Donald Trump and Kim, North Korea and the US agreed to work toward the "complete denuclearization of the Korean peninsula" -- a phrase that the North Koreans have long interpreted to mean the US also has an obligation to remove any nuclear capable weaponry it has on Korean soil.

But after the summit, Trump administration officials, including former Secretary of State Mike Pompeo, said the agreement pledged North Korea to the complete, verifiable and irreversible dismantlement of its nuclear program, despite the fact that it said nothing of the sort.

North Korea would go on to describe Pompeo as a "diehard toxin" whose "unilateral and robber-like denuclearization demands" contravened the spirit and letter of the Trump-Kim summit. An unnamed North Korean official told the state Korean Central News Agency in March 2020 that "listening to Pompeo's ludicrous language made us give up on any hopes for dialogue."

Narang said that the Biden officials' insistence on adopting the same emphasis on North Korean denuclearization "likely isn't helping, when you insist on something they've rejected flat out of hand."

Former officials and experts also noted that Biden administration officials' commitments not to lift tariffs on North Korea during confirmation hearings did not go unnoticed, which could be one factor driving Pyongyang's decision not to engage directly with the US.

North Korea following meetings closely

Kim will also be keeping a close eye on meetings in Seoul and Tokyo between Blinken and Austin and their Japanese and South Korean counterparts this week and an Alaska meeting between Blinken, national security adviser Jake Sullivan and their Chinese counterparts. North Korea is expected to factor into those conversations, particularly with the South Koreans.

"What if the US and China come out of their meetings this week and make it clear that they are headed for escalating US-China tensions? If you are Kim Jong Un you would read that as meaning that it is less likely that China will put the squeeze on North Korea," said Anthony Ruggiero, a former National Security Council official. "If that happens, maybe Kim now knows he can go to China to buy more pieces for its nuclear programs, or to go to China and sell more coal. That would be a bad sign for the future of any US-North Korea diplomacy."

Aum also posited that the North Koreans may also be signaling "that they want to engage with the US at a higher level, because there's been the precedent that was set with the leader-level summits between Trump and Kim."

Efforts at working level talks between North Korean and Trump administration officials were largely rebuffed by Pyongyang, and the few meetings that did occur yielded no tangible results.

Despite Kim Yo Jong's warning to the new administration, North Korea did not greet the arrival of the new US president with a test of their missiles or other weaponry, as is often the case.

Aum said that he doesn't think they'd "want to do anything to provoke the US prior to some greater signal that the US is going to take a very hostile approach."

However, in recent days there has been activity at North Korea's nuclear facility, Yongbyon, according to analysis of new satellite images published by 38 North, a prominent North Korea monitoring group.

And the official travels in the region, the military exercises and Biden's meeting with Japanese Prime Minister Yoshihide Suga in April could still push Pyongyang toward some sort of provocation.