President Donald Trump is back at the White House after a three-day visit to China, a crucial meeting between the world's largest economies and the first such visit by an American president in nearly a decade.Both the U.S. and China committed to enhancing cooperation, in stark contrast to the tense trade war last year that drove tariffs into the triple digits. Both sides have since lowered import taxes as part of a temporary truce. Asked if the truce would be extended, Trump told reporters that tariffs were not discussed during his meetings with Chinese President Xi Jinping because "it wasn't brought up." Trump's power to unilaterally impose certain tariffs was limited by a U.S. Supreme Court decision earlier this year.Chinese Foreign Minister Wang Yi said the two sides agreed to establish a board to promote expanded trade under a framework of reciprocal tariff reductions.No concrete trade deals were announced before Trump left China, and it was not immediately clear if Beijing would commit to new orders of U.S. soybeans and beef. After the summit, the aircraft manufacturer, Boeing, confirmed its first major sale to China in nearly a decade. "We did great trade deals. We have great relationships, and a lot of things have happened, and you'll be hearing about them, but that was a tremendous success. I think it really was a historic moment," Trump told reporters after touching down in Washington, D.C., on Friday. But tensions surrounding Taiwan loomed large over the visit. China warned that mishandling relations with Taiwan, a self-governed island that Beijing claims as its territory, could lead to open conflict. Trump said he has not yet decided whether to proceed with a multibillion-dollar weapons package for Taiwan, comments that have raised concerns among some Republicans. When asked if U.S. policy on Taiwan had changed during an interview on Fox News Channel's "Special Report," Trump said, "No, nothing's changed. I will say this, I'm not looking to have somebody go independent and, you know, we're supposed to travel 9,500 miles to fight a war. I'm not looking for that. I want them to cool down. I want China to cool down." The ongoing conflict with Iran was also discussed during the summit. Trump said there was agreement on the need to reopen the Strait of Hormuz for oil shipments and that Xi offered to help negotiate an end to the conflict, though China did not immediately confirm that.China is one of Iran's largest trading partners. Trump previously expressed hope that Beijing could use its leverage to push Iran toward the U.S. negotiating position. At least publicly, China has said the concerns of all parties should be taken into account. Trump said that Xi agreed with him that Iran cannot obtain a nuclear weapon and assured him that China would not provide Iran with military equipment. Trump also stated that he will decide in the coming days whether to lift sanctions on Chinese companies that purchase Iranian oil.