Kim Yo Jong, the sister of North Korean leader Kim Jong Un, released a statement on Sunday morning reporting that U.S. President Donald Trump had written a “personal letter” to her brother and praised his efforts in the fight against the coronavirus.

In the statement, published by the official Korea Central News Agency (KCNA), Kim Yo Jong said that Trump had “explained his plan to propel” U.S.-DPRK relations, “expressed his intent” to cooperate on the coronavirus pandemic.

But she also warned that the “excellent” personal relations between the two leaders do not mean that the two countries are suddenly getting along after months of diplomatic stalemate.

The two leaders have not met since June.

“We regard it as a good judgment and proper action for the U.S. president to make efforts to keep the good relations he had with our Chairman by sending a personal letter again at a time as now when big difficulties and challenges lie in the way of developing the bilateral relations, and think that this should be highly estimated,” Kim Yo Jong said, according to KCNA.

“In the letter, [Trump] also explained his plan to propel the relations between the two countries of the DPRK and the U.S. and expressed his intent to render cooperation in the anti-epidemic work, saying that he was impressed by the efforts made by the Chairman to defend his people from the serious threat of the epidemic,” she said.

North Korea has denied having any coronavirus infections within its borders — a claim doubted by many experts and observers — while the outbreak has ballooned over the last week in the United States.

“Saying that he values his relations with Chairman Kim Jong Un, President Trump said that there were difficulties in letting his thoughts known because communications were not made often recently,” Kim said.

“He expressed his willingness to keep in close touch with the Chairman in the future,” she said.

“We view such a personal letter of President Trump as a good example showing the special and firm personal relations with Chairman Kim Jong Un,” she said, adding that “Chairman Kim Jong Un also mentioned his special personal relations with President Trump again and appreciated the personal letter.”

Trump and Kim Jong Un have met three times — something no sitting U.S. President had done before — and Trump has touted those meetings as evidence that his foreign policy has been a success.

The leader’s sister, however, on Sunday contrasted the two men’s allegedly strong personal relationship with the much rockier relationship between the two countries — and warned against being too optimistic.

“Fortunately, the personal relations between the two top leaders are not as far away as the relations of confrontation between the two countries, and they are very excellent,” she said.

“But the relations between the DPRK and the U.S. and their development should not be judged in haste in the light of the personal relations between the two top leaders, and furthermore, neither predictions nor expectations should be made based on them,” she continued.

“As they are the close relations between the two men representing the two countries, they would have positive impact but nobody knows how much the personal relations would change and lead the prospective relations between the two countries, and it is not something good to make hasty conclusion or be optimistic about it,” she said.

Kim Yo Jong, one of the highest-ranking officials in North Korea, also cautioned that Washington and Pyongyang will be unlikely to get along if the DPRK still feels the need to defend itself against the U.S. and the “cruel environment” she says it has created.

The U.S. and United Nations have imposed a wide array of punitive sanctions on North Korea because of its nuclear weapons program.

The debate over sanctions relief — along with denuclearization — has become one of the most contentious unresolved issues between the two countries.

The North also says it vehemently opposes the U.S. military presence on the Korean peninsula — another part of what Pyongyang describes as Washington’s “hostile policy” against the North.

“If impartiality and balance are not provided and unilateral and greedy intention is not taken away, the bilateral relations will continue to aggravate,” Kim said.

“In my personal opinion, I think that the bilateral relations and dialogue for them would be thinkable only when the equilibrium is kept dynamically and morally and justice ensured between the two countries, not merely by the personal letter between the two leaders,” she continued.

“Even at this moment we are working hard to develop and defend ourselves on our own under the cruel environment which the U.S. is keen to ‘provide,'” she said.

North Korea conducted its third missile test of the month on Saturday morning.

The U.S. and South Korea, by contrast, canceled one scheduled round of military exercises because of the coronavirus outbreak, although South Korea’s defense minister, Jeong Kyeong-doo, said in an op-ed published on Friday in the publication Defense News that the two allies would likely restart some drills in a modified way.

Kim’s statement Sunday appeared to end on a more hopeful note — that the U.S.-DPRK relationship might eventually match the Trump-Kim relationship — but suggested that in the meantime, the North would not back down from its current path.

“We try to hope for the day when the relations between the two countries would be as good as the ones between the two top leaders, but it has to be left to time and be watched whether it can actually happen,” she said, according to KCNA.

“However, we will never lose or waste time for nothing, but will keep changing ourselves to be more powerful for that time just as how we made ourselves for the past two years,” she continued.

“At the end I would like to extend sincere gratitude to the U.S. president for sending his invariable faith to the Chairman.”

Edited by Oliver Hotham