BEIJING, MAY 14 China's Xi Jinping warned President Donald Trump on Thursday that the two countries could clash over Taiwan if the issue was not handled properly, an unusually harsh admonition that stood in contrast to the American leader's praise for his counterpart. The exchange at a highly anticipated summit in Beijing underscored just how far apart Trump and Xi remain on thorny issues, including the war in Iran, trade disputes and Washington's relations with Taiwan, which is self-ruled but which China claims as part of its territory. It also suggested that Trump's three-day visit to China is likely to be longer on pageantry and symbolism than substantive political or economic breakthroughs. The pair met for about two hours behind closed doors at the Great Hall of the People after an elaborate welcome ceremony featuring booming cannons, a band playing 'The Star-Spangled Banner' and China's national anthem, and hundreds of school children waving flowers and American and Chinese flags. According to a post on X by Chinese Foreign Ministry spokesperson Mao Ning, Xi told Trump that 'the Taiwan question is the most important issue in China-U.S. relations.' 'If it is handled properly, the bilateral relationship will enjoy overall stability. Otherwise, the two countries will have clashes and even conflicts, putting the entire relationship in great jeopardy,' she wrote. That came after a brief public exchange before the meeting began in which Trump offered platitudes, telling Xi: 'You're a great leader. Sometimes people don't like me saying it, but I say it anyway, because it's true.' 'It's an honor to be your friend,' Trump said before promising that 'the relationship between China and the USA is going to be better than ever before.' Xi was far more stark than Trump in his opening remarks, expressing hope that the U.S. and China could avoid conflict and asking 'whether the two countries can transcend the 'Thucydides Trap' and forge a new model for relations between major powers.' That's a term, popular in foreign policy studies, that refers to the idea that when a rising power threatens to displace an established power, the result is often war. Xi's use of the term as Trump offered optimism was noteworthy and foreshadowed his closed-door comments about Taiwan. Xi nonetheless struck a more conciliatory tone when describing the overall relationship. 'Cooperation benefits both sides, while confrontation harms both,' Xi said. 'The two countries should be partners rather than rivals.' Economic questions sparked by the Iran war loom After their meeting, Xi took Trump on a Tour of Beijing Temple of Heaven, and the pair were planning to attend a state banquet in the evening. In its summary of what said privately, the White House said the meeting touched on ways to enhance economic cooperation, including expanding market access for American businesses into China and increasing Chinese investment into U.S. industries. That assessment didn't mention Taiwan directly, but, in relation to Iran, said both sides had agreed that the Strait of Hormuz, a crucial waterway for oil and natural gas, must remain open. The strait's closure has stranded tankers and caused energy prices to spike, threatening global economic growth. The war and its effects are dominating Trump's domestic agenda and stoking fears about the prospect of a weakening U.S. economy as November's midterm elections - when Republicans will be looking to maintain control of Congress - approach. China is the largest purchaser of Iranian oil, and Secretary of State Marco Rubio said in an interview with Fox News' Sean Hannity that Trump would make the case for Beijing to exert its influence on Iran, noting that administration officials would underscore that 'economies are melting down because of this crisis' which means consumers are 'buying less Chinese product.' It's not clear if Trump persuaded Xi to wield its influence. The White House said Xi opposed to any implementation of tolls on vessels crossing the strait and expressed interest in China potentially purchasing more U.S. oil to reduce Chinese dependence on Gulf oil in the future. Taiwan issues remain contentious Xi's warning about Taiwan reflects China's displeasure with a U.S. plan to sell weapons to the island. The Trump administration has approved an $11 billion arms package for Taiwan, but has yet to begin fulfilling it. The U.S. has a longstanding commitment to help the island defend itself if attacked, but Trump has shown greater ambivalence toward Taiwan, fueling speculation about whether the president could be persuaded to dial back American support. Taiwan, meanwhile, said it was grateful for Washington's 'long-term support.' 'The government views all actions that contribute to regional stability and the management of potential risks from authoritarian expansion positively,' Michelle Lee, a spokesperson for Taiwan's premier, told reporters. She added that the U.S. 'has also repeatedly reiterated its firm and clear position of support for Taiwan.' US still hopes to secure trade wins The White House has insisted that Trump wouldn't be making the trip without an eye toward securing results before he leaves, suggesting there could be announcements coming on trade. That could include a Chinese commitment to buy U.S. soybeans, beef and aircraft. Trump administration officials also want to work toward establishing a Board of Trade with China to address commercial differences between the countries. The leaders discussed trade on Thursday, with Xi saying that China's door of opportunity will open wider. Xi also met with a collection of U.S. business leaders who accompanied Trump to China. But neither side has yet offered concrete details on what might come out of Trump's trip at a time when Beijing's close economic ties to Iran could complicate matters. George Chen, a partner at The Asia Group consultancy, said Xi has made his ''red line' crystal clear' on Taiwan. But Chen said Xi also signaled a welcoming tone on the economic front and a desire to ensure the U.S. business community that China is a place where profits can flow. The U.S. and China reached a trade truce last year that calmed each side's threats to impose steep tariffs on the other. The White House says there have been ongoing discussions and mutual interest in extending the agreement. The leaders also discussed further stemming the flow of fentanyl precursor chemicals into the United States, and increasing Chinese purchases of U.S. agricultural products, according to the White House.