Arriving in China’s Forbidden City on Wednesday, Donald and Melania Trump quickly fell back into a familiar pattern with Chinese President Xi Jinping, bonding over tea, an evening of opera, and a video of Ivanka Trump’s daughter Arabella reciting Chinese poetry. Although dinner might have been convivial, the diplomatic purpose of Trump’s trip is delicate: during his stay in China, he reportedly hopes to persuade Xi to increase pressure on North Korea over its ballistic and nuclear programs by stemming the flow of Chinese oil, deporting the thousands of North Koreans living in China, and closing North Korean bank accounts.

Despite little in the way of new leverage, Trump has approached this task with gusto. Earlier Wednesday, forced to cancel a traditional trip to the demilitarized zone between North and South Korea due to fog, he delivered a surprisingly measured speech to South Korea’s National Assembly, bereft of any sniping Rocket Man references. “We will offer a path to a much better future,” he said, directly addressing his adversary Kim Jong-un. “It begins with an end to the aggression of your regime, a stop to your development of ballistic missiles, and complete, verifiable and total denuclearization.” At recent meetings near Geneva and in Moscow, Pyongyang’s representatives showed interest in talks with the U.S., provided that disarmament is not on the table.

Trump was careful to cut his conciliatory tone with a more ominous option. “This is a very different administration than the United States has had in the past,” he said. “Do not underestimate us, and do not try us.”

“The weapons that you are acquiring are not making you safer, they are putting your regime in grave danger,” he continued. “Every step you take down this dark path increases the peril you face.”

Sketching a grim picture of life in the “cult”-like North, Trump highlighted a roster of human rights abuses, including forced labor, famine, and frequent detentions. Citizens would rather bribe government officials to be sold into slavery rather than remain in their country, he said, and “ethnically inferior” children are aborted, or killed after being born. (Last month, a U.S. State Department report on North Korea raised forced abortions among the serious human-rights abuses committed by Pyongyang.)

In contrast, Trump lavished praise on South Korea. Highlighting its economic growth and lengthening life-span, he honed in on one of his favorite topics—golf—congratulating the South Korean women who finished in the top four positions at the tournament held earlier this year at Trump National Golf Club in New Jersey. “What you have built is truly an inspiration,” he said.

Typically, Kim does not take well to Trump-administered attacks. In September, when the president threatened to “totally destroy North Korea,” he released a rare personal statement, calling Trump a “mentally deranged U.S. dotard” who would “pay dearly” for his threats. Predictably, then, Pyongyang showed no sign of relinquishing its nuclear arsenal Wednesday. “The world is undergoing unprecedented throes because of Trump, a notorious political heretic,” state-run newspaper Minju Joson said in a commentary, according to the Korean Central News Agency.

“The U.S. must oust the lunatic old man from power and withdraw the hostile policy towards the DPRK at once in order to get rid of the abyss of doom,” it added, abbreviating the country’s formal name, the Democratic People’s Republic of Korea. It remains unclear if the remarks were made in response to Trump’s speech in Seoul, or were published before.

As North Korea bristled, Trump used his speech to urge Russia and China to to help resolve the threat of a nuclear conflict by severing ties and trade with Pyongyang. “It is our responsibility and our duty to confront this danger together,” he said. “The longer we wait, the great[er] the danger grows and the fewer the options become.” China is North Korea’s most powerful diplomatic ally and trading partner, and Trump has long argued that Beijing has the ability to muzzle Kim’s regime. Indeed, as Air Force One flew to the Forbidden City, a senior White House official told reporters that China should cut financial links with North Korea that the U.S. believes violates sanctions, according to the Wall Street Journal.

Arguably, though, Trump doesn’t understand the limitations of the relationship between China and North Korea, recently strained by Xi’s decision to restore relations with South Korea. As the New York Times notes, although the two nations fought together in the Korean war, and are economically linked, some Chinese experts call the bond a “fake alliance.” The waning relationship between the two was fractured when Kim executed his uncle Jang Song-thaek, who had served as the primary link between the North and China’s senior leadership.