China and the United States agreed to create a communication channel for addressing issues related to artificial intelligence and to speed up efforts on military crisis communications after a three-day summit between President Xi Jinping and President Donald Trump in Washington, the two governments said. The leaders also decided to continue working together through a Board of Trade focused on specific bilateral issues. The White House announced that the board started operating this week. Although the summit did not lead to major breakthroughs, analysts suggested that the steps toward cooperation were significant because they created working groups that could help prevent disputes from escalating. Xi returned to Beijing on Saturday, according to the state-run Xinhua News Agency. During the visit, Mr. Trump showed an unusually warm attitude toward Xi, despite having previously escalated a trade war with China that had global consequences. The two sides agreed to sign a memorandum of understanding on strengthening crisis communications and preventing crises between the two militaries, according to China's Foreign Ministry. The one-page statement from the Chinese side provided few details. Both countries will set up a communication mechanism for AI-related incidents, to discuss related risks and benefits, with a specific AI dialogue planned for November. The White House said the two leaders agreed to use the term "super intelligence" rather than "artificial intelligence" to describe the technology. Mr. Trump has been vocal about preferring this alternate term. "I call it SI because it's a much better name," he told reporters on the White House's south lawn. "It's a much more accurate name because when you say the other, it means it's fake. Artificial means it's fake, and it's not fake." Mr. Trump also indicated that there would be limits on what the U.S. would share with China and said that Washington would not slow its AI efforts. "The United States of America is not going to be putting on brakes," he said. "They want to stop our progress because we're leading China by a lot and we're going to keep it that way." He added, "I would rather not integrate because we're leading by a lot. When you're leading, you don't open it up to each other. We're leading by at least a year, maybe a year and a half. Some people say two years. I'm not looking to open it up." The statement from China said both sides will continue to work together on reducing reciprocal tariffs on about $30 billion worth of goods. During the summit, the two leaders agreed to extend a trade truce by two months. The White House statement said China agreed to import at least 10 million metric tons of coal from the U.S. in 2027 and 2028. Most of the reduction in tariffs is aimed at non-sensitive goods, such as agricultural products or holiday decorations. The two countries also established the Board of Investment to "discuss potential investment opportunities and investment-related impediments and to provide a structured channel for the two sides to address commercially meaningful investment-related issues," the White House said. Both governments said Iran should honor its stated commitment not to develop nuclear weapons. They also said no country should charge tolls on international waterways, an apparent reference to the Strait of Hormuz, where traffic has fallen significantly since the U.S. war with Iran began.