President Donald Trump has delivered what appeared to be a sharp rebuke to China, railing against trade practices he said have put Americans out of work and warning that the US would no longer "turn a blind eye" to trade abuses.
Speaking at a gathering of CEOs at the Asia-Pacific Economic Co-operation (Apec) summit in Danang, Vietnam, hours after leaving Beijing, he said: "From this day forward we will compete on a fair and equal basis."
"We are not going to let the United States be taken advantage of anymore. I am always going to put America first."
It was a striking change of tone from the day before, when he had set aside his previous blistering rhetoric in favour of friendly overtures to China as he sought to establish a more balanced trade relationship.
But on Friday, he was back to blunt. He told the executives that he was happy to enter into bilateral trading agreements - but only if they are reciprocal and fair.
Without singling out China by name, Mr Trump argued that the US had adhered to World Trade Organisation principles, only to be taken advantage of by countries that had ignored the rules and engaged in harmful practices such as product dumping, currency manipulation and government subsidising of goods.
"Such practices, along with our collective failure to respond to them, hurt many people in our country," he said, describing "jobs, factories and industries" he said were "stripped out of the United States and out of many countries" as a result.
"We can no longer tolerate these chronic trade abuses and we will not tolerate them," he said.
In the speech, he said he had spoken "openly and directly" with Chinese President Xi Jinping during his visit about "China's unfair trade practices and the enormous trade deficits they have produced with the United States".
Mr Trump said China's trade surplus, which stood at 223 billion US dollars for the first 10 months of the year, was unacceptable, and repeated his language from Thursday when he said he did "not blame China" or any other country "for taking advantage of the United States on trade".
But he went on to say that the US would "no longer turn a blind eye to violations, cheating or economic aggression".
"We will no longer tolerate the audacious theft of intellectual property. We will confront the destructive practices of forcing businesses to surrender their technology to the state and forcing them into joint ventures in exchange for market access. We will address the massive subsidising of industries through colossal state-owned enterprises that put private competitors out of business, all the time," he said.
All are allegations the US has lodged against China.
Mr Trump also continued to talk tough against North Korea and its development of nuclear and ballistic missiles weapons, as he has throughout his trip.
"The future of this region and its beautiful people must not be held hostage to a dictator's twisted fantasies of violent conquest and nuclear blackmail," he said.
He referenced his address earlier this week in South Korea when he called on countries to unite against North Korea. He said "every single step the North Korea regime takes toward more weapons is a step it takes into greater and greater danger".
Apec is the first of several summits Mr Trump is scheduled to attend on his first official visit to Asia. It will be a change in pace for the president, who has spent much of the week basking in elaborate welcome ceremonies and banquets, and meeting the leaders of Japan, South Korea and China.
His schedule for Friday includes an official welcome event for world leaders attending the summit and their spouses, along with a gala dinner and cultural performance, before formal talks begin on Saturday.