He said North Korea would continue to take the “toughest stand” against the U.S., but that if Washington dropped its demands for denuclearization, “there is no reason why we cannot get on well.”

That leaves the door open for the resumption of diplomacy. President Donald Trump, who met with Kim three times during his first term, has expressed interest in another face-to-face.

Kim had more contentious words for U.S. ally South Korea, describing it as his country’s “most hostile” relationship. He dismissed South Korean President Lee Jae Myung’s recent efforts to improve relations, saying the North could “launch any action” if Seoul threatened its security and that its neighbor risked “complete collapse.”

The South Korean government said Thursday that it would continue to pursue its policy of peaceful coexistence.

Earlier in the week, Kim was re-elected general secretary of the Workers’ Party. His reappointment reinforces that “even amid domestic and external crises, there is no alternative to Kim Jong Un’s leadership,” Lim said.

For Kim, the party congress is also an opportunity to reinforce the authority of his family, which has ruled North Korea since its founding in 1948 and signals successors well in advance.

Earlier this month, South Korea’s National Intelligence Service told lawmakers it believed that Kim Ju Ae had entered the “designation stage” of the succession process after a period of training.

“Since late last year, North Korea has been emphasizing her status as the top-ranked figure in the protocol order,” the agency said, citing her attendance at military-related events, her visit to the Kumsusan Palace of the Sun — a symbol of North Korea’s dynastic rule — and “the fact that she has offered opinions on certain policies during on-site inspections.”

Others have expressed skepticism.

While the younger Kim’s status in the family has risen, there is insufficient evidence to assert that she is on the verge of being named her father’s successor, said Yang Moo-jin, a distinguished professor at the University of North Korean Studies in Seoul.

“Claiming that she ‘offered policy opinions’ simply because she may have said something when asked beside him amounts to an overly subjective and speculative assumption,” he said.

There were also no signs at the party congress that Kim Jue Ae had received an official party title or that there are plans for a meeting on successor designation, both of which have been part of the process in the past.

Still, Lim said, even if no formal steps have been taken, “efforts to lay the groundwork for Kim Ju Ae’s future power base are likely to start being carried out behind the scenes in a more sophisticated way.”