President Donald Trump has denounced China for unfair trade practices just a day after he heaped praise on President Xi Jinping in Beijing.
At a summit of Asian leaders keen on regional trade pacts, Mr Trump delivered a roaring "America first" message.
"We are not going to let the United States be taken advantage of any more," Mr Trump told CEOs on the sidelines of the Asia-Pacific Economic Cooperation (Apec) conference.
"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."
The president - who pulled the United States out of the Pacific Rim trade pact known as the Trans-Pacific Partnership - said the US would no longer join "large agreements that tie our hands, surrender our sovereignty and make meaningful enforcement practically impossible".
Instead, he said, the US will pursue one-on-one trade deals with other nations that pledge fair and reciprocal trade. The message stood in sharp contrast to the behind-the-scenes negotiations taking place among other countries at the summit on a successor to TPP.
As for China, Mr Trump said he had spoken "openly and directly" with Mr Xi about the nation's abusive trade practices and "the enormous trade deficits they have produced with the United States".
It was a stark change in tone from the day before, when Mr Trump was Mr Xi's guest of honour during a state visit in Beijing. There, Mr Trump opted for flattering Mr Xi and blaming past US presidents for the trade deficit.
Mr Trump said China's trade surplus, which stood at 223 billion dollars for the first 10 months of the year, was unacceptable. He 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 Mr Trump added forceful complaints about "the audacious theft of intellectual property," the ''massive subsidising of industries through colossal state-owned enterprises," and American companies being targeted by "state-affiliated actors for economic gain" - without singling China out by name.
US officials have raised similar concerns in the past about China, especially with regard to intellectual property.
On Saturday, Trump attended meetings with leaders of the 21-member Apec countries
In a major breakthrough, trade ministers from 11 nations remaining in the Trans-Pacific Partnership - representing roughly 13.5% of the global economy - said on Saturday they had reached a deal to proceed with the free-trade pact after it was thrown into doubt when Mr Trump abandoned it.