Speaking at the Asia-Pacific Economic Cooperation summit in Vietnam, the president also warned against mistreating his country, accusing some countries in the region of "product dumping, subsidized goods, currency manipulation and predatory industrial policies."
"We can no longer tolerate these chronic trade abuses, and we will not tolerate them," Trump said.
"From this day forward, we will compete on a fair and equal basis," he added. "We are not going to let the United States be taken advantage of anymore. I am always going to put America first the same way that I expect all of you in this room to put your countries first."
Additionally, Washington will "no longer tolerate the audacious theft of intellectual property, we will confront the destructive practices of forcing businesses to surrender their technologies to the state and forcing them into joint ventures in exchange for market access," he said.
Many U.S. firms operating in China have complained of such policies.
Trump said he did not blame China, the world's second-largest economy, or other countries for "taking advantage of the U.S. on trade," repeating a message he delivered in Beijing the previous day.