Thomas Maresca

Special to USA TODAY

SEOUL – North Korean leader Kim Jong Un is in China, where he will meet with President Xi Jinping, Chinese and North Korean state media reported on Tuesday.

The trip, which is Kim’s fourth to China, came at the invitation of President Xi Jinping, according to news agency Xinhua, and will last until Thursday.

Kim was accompanied by his wife, Ri Sol Ju, and a delegation of high-ranking North Korean officials and traveled by private train across the border to China, North Korean newspaper Rodong Sinmun reported.

The North Korean dictator will be celebrating his 35th birthday on Tuesday.

Kim’s visit comes in the wake of an announcement on Sunday by President Donald Trump that Washington and Pyongyang were in negotiations over a location for a second summit, saying that it would be revealed “probably in the not-too-distant future.”

A South Korean newspaper reported on Monday that Hanoi, the capital of Vietnam, was being considered as the site for the next Trump-Kim summit. Citing high-level sources in Seoul and Washington, Munhwa Ilbo reported that officials from the U.S. and North Korea have met in Hanoi to discuss scheduling the meeting.

Previously, Washington has suggested Vietnam, a communist nation with a rapidly developing economy, could serve as a model for North Korea in the future.

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During a visit to Hanoi in July, Secretary of State Mike Pompeo called on North Korea to replicate Vietnam’s economic “miracle.”

“In light of the once-unimaginable prosperity and partnership we have with Vietnam today, I have a message for Chairman Kim Jong Un: President Trump believes your country can replicate this path,” Pompeo said on that visit.

Kim’s current trip to China may be further evidence that a meeting with Trump is getting closer to reality. The North Korean leader went to China before and after his summit with Trump last June.

While the isolated state has dramatically raised its international profile over the past year, China remains North Korea’s closest ally and most important trading partner, accounting for 90 percent of its exports since 2000, according to a report from the Korea Development Institute.

The visit by Kim allows China to show the international community that it still plays a major role in North Korean issues, said Lee Seong-hyon, director of the Center for Chinese Studies at The Sejong Institute, a Seoul-based think tank.

“A visit like this is a very good occasion for China to prove to the world that it’s not sidelined,” Lee said.

Beijing may also be using this meeting with Kim as leverage in its ongoing trade war with Washington, which imposed tariffs on $250 billion in Chinese goods, causing China to retaliate with tens of billions of dollars in tariffs of its own. A U.S. delegation is currently in Beijing for two days of talks as the world’s two largest economies are looking to strike a new trade deal.

“China might use this occasion to nudge Kim to be more willing to make concessions in denuclearization steps as a diplomatic favor to Washington,” Lee said. “That will be seen as a goodwill gesture that China is on the same page with the United States on North Korea issues.”

A second Trump-Kim summit would seek to push forward a diplomatic process that has stalled out since their June meeting in Singapore.

While that meeting produced a declaration that North Korea would work toward a “complete denuclearization of the Korean peninsula,” details and a timeline for carrying out the agreement remain vague.

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Pyongyang is looking for relief of punishing international sanctions in exchange for steps it has already taken, such as dismantling a nuclear testing site, while Washington is holding out for complete denuclearization.

Kim reiterated a call for sanctions relief on a televised New Year’s Day address, saying he was ready to meet again with Trump “anytime” but warning the U.S. not to test North Korea’s patience over the sanctions, threatening that it may have to find a “new way” to defend its interests.

Trump said on Sunday that sanctions would remain “in full force” until North Korea provided “very positive proof” of results.

While the birthdays of Kim’s father, previous “Supreme Leader” Kim Jong Il, and grandfather, North Korean founder Kim Il Sung, are celebrated as national holidays, Kim Jong Un’s birthday is not.

The only example of Kim being honored in public on his birthday was in 2014, when former NBA star Dennis Rodman sang “Happy Birthday” to him before an exhibition basketball game in Pyongyang.