SEOUL (BLOOMBERG) - A fresh warning from Kim Jong Un - coming just as South Korea's Moon Jae-in arrived in Washington to meet United States President Donald Trump - placed new urgency on the allies' efforts to restart nuclear talks.
The North Korean leader urged top ruling party members on Wednesday (April 10) to deal a "severe blow to hostile foreign forces" by resisting sanctions against the country, according to the official Korean Central News Agency.
While the report included no direct threat of action, it underscored Mr Moon's challenge in finding common ground between Mr Kim's demands for economic relief and Mr Trump's insistence on greater disarmament commitments.
"North Korea is suggesting that it would close the door to dialogue if the leaders of South Korea and the United States do not show flexibility to sanctions," said Dr Shin Beom-chul, director at the Seoul-based Asan Institute for Policy Studies' Centre for Security and Unification.
"The remarks would be quite a burden for President Moon Jae-in. If sanctions are strengthened, North Korea may not return to dialogue for a while."
Mr Moon hopes a direct appeal at the White House on Thursday can keep his efforts to build a lasting peace on the Korean peninsula from slipping away after Mr Trump walked away from his summit with Mr Kim in Hanoi.
Not only would new provocations put Seoul back at risk, but Mr Moon has also staked much of his presidency on building ties between South Korea's closest ally and its increasingly well-armed rival.
Mr Moon's administration raised expectations for a deal before the Feb 28 meeting and was caught off guard when the two leaders left Vietnam without an agreement. His approval rating fell to a record low of 41 per cent last week, according to Gallup Korea, compared with 83 per cent in the wake of his first meeting with Kim last April.
One US administration official said Wednesday that Mr Trump liked Mr Moon, but believed that the US President and Mr Kim were best positioned to mediate their own relationship.
Mr Trump wasn't convinced that the South Korean leader could bridge the divide after the collapse of the Hanoi talks, said the official, who asked not to be identified discussing the President's thinking.
"Moon is more determined now than ever to persuade Trump to return to the bargaining table with North Korea," said Mr David Kim, a research analyst at the Stimson Centre and a former official at the US State Department. "Moon has played a critical role in getting these two leaders together and I believe he could pull it off again if they can agree to a process moving forward."
An immediate concern for Mr Moon is discouraging Mr Kim Jong Un from any actions that could provoke Mr Trump and return the two sides to the familiar cycle of threats and counter-threats. North Korea is planning to celebrate the birth of its founder - Mr Kim's grandfather Kim Il Sung - next Monday, an occasion that the regime has sometimes marked with shows of military might.
A top North Korean diplomat told reporters in Pyongyang last month that Mr Kim would decide "in a short period of time" whether to continue his freeze on bomb and missile tests. In the meantime, the regime has sent diplomats to potential areas of alternative support such as Moscow, fuelling speculation of a possible Kim trip to Russia.
North Korea has also ignored South Korean requests for working-level talks, briefly withdrawing officials from a joint liaison office, and criticised Mr Moon's government for supporting to US-led sanctions and military drills. The moves signalled that Mr Moon's achievements since signing a joint declaration with Mr Kim in the demilitarised zone last year could unravel without action.
Mr Lee Do-hoon, South Korea's top envoy to talks, told a forum in Seoul that the parties were in a "race against time".
"If we let time pass by without dialogue or negotiation, the two Koreas and the United States will end up in a situation that does not benefit anyone," he said. "It is high time that the United States and North Korea get back together."
Mr Moon's office has reached out to North Korea about holding another summit with Mr Kim on April 27, to mark the one-year anniversary of their first meeting, the Chosun Ilbo newspaper reported, citing an unidentified government official.
Getting talks back on track might require progress on two fronts: Convincing Mr Trump to accept incremental steps short of "complete denuclearisation" and getting Mr Kim to agree to an end goal. South Korean officials have expressed the need for a "good enough" or "early harvest" deal that can build momentum - without elaborating on what such an agreement would involve.
That's where Mr Moon risks opening a rift with Mr Trump. While the US leader has expressed a desire to maintain his "very good relationship" with Mr Kim, his decision to leave the Hanoi meeting empty-handed signals that he needs a more significant concession than the ageing nuclear plant North Korea was prepared to give up.
Mr Moon will probably use the meeting to continue to press for relaxing sanctions to resume stalled inter-Korean economic projects such as joint factory park and mountain resort - even through waivers could be revoked.
Some 30 representatives of South Korean companies with interests in the Gaeseong industrial park on the northern side of the border signed a petition calling on Mr Trump to exempt the project from sanctions. The US has so far been cool to the proposal, which would provide the cash-strapped regime with a jolt of foreign currency.
"My sense is that Trump is not willing to accept this," said Mr Ramon Pacheco Pardo, Korea Foundation-Vrije Universiteit Brussels Korea chair at the Institute for European Studies. "But I also think that it would not make sense for Seoul to simply stop pushing these plans due to the setback in Hanoi."