Following Russia's seizure of three Ukrainian ships, Trump threatened to cancel planned talks in Buenos Aires with President Vladimir Putin.
The Kremlin said it had not been notified and only learned about it from the tweet.
"China has sent a clear signal to oppose protectionism and back the multilateral trading system, which will facilitate an open world economy", Mr Ruan said.
Presidents Donald Trump and Xi Jinping are expected to address what the USA calls China's theft of American technology and IP when they meet Saturday evening at the two-day G20 summit in Buenos Aires.
China's head however has vowed that China would boost protection of intellectual property.
But foreign firms in China complain that such promises are all too routine, and analysts doubt that Trump and Xi's dinner will serve up much beyond a commitment to negotiate further.
Asked if China was seeking to prevent more USA tariffs at the high-stakes meeting, the ministry's spokesman, Gao Feng, said economic teams from both sides were in contact to implement a "consensus" reached by Mr Trump and Mr Xi in a phone call this month.
Stepping away from the sealed security zone and ceremonial pomp of the Group of 20 summit, Indian Prime Minister Narendra Modi brought a message dear to his heart to host Argentina - the value of yoga. "Maybe I won't have the meeting", he said.
In a tweet on Thursday, however, Trump said, "Billions of Dollars are pouring into the coffers of the United States of America because of the Tariffs being charged to China, and there is a long way to go".
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At the very least it seems unlikely that prosecutors will request a lighter sentence in response to Mr Manafort's cooperation. Manafort said in the same filing he disagreed with Special Counsel Robert Mueller's assertion that he lied to investigators.
It has contrived all sorts of non-tariff barriers to ensure foreign businesses don't get any serious foothold in the Chinese market.
Trump and Xi are scheduled to meet on Saturday to discuss trade amid increasing tensions between the world's top two economies.
G20 leaders, whose countries account for four-fifths of the world's economic output, first met in November 2008 to forge a united front against the global financial crisis.
Trump has repeatedly shown his disdain for global summitry by blocking final communique at other recent gatherings such as the G7 and the Asia-Pacific bloc APEC.
But with a major United Nations meeting on climate change starting next week in Poland straight after the G20, United Nations chief Antonio Guterres said in Buenos Aires that "this is a make-it-or-break-it moment".
In last year's G20 summit in Germany, discussions were held on sustainable development and volatility in global currency markets at length. And in the renegotiated North American Free Trade Agreement, now called the U.S. -Mexico-Canada Agreement, countries drew up what's called a side-letter on autos to address the issue separately.
"President Trump is right to have zeroed in on China's unfair trade practices, but a trade war with China isn't good for the world's economy over the long term, and it's not good for the USA economy either", said Delaware Sen. The U.S. had a trade surplus in cars with China past year.
The weekend G20 gathering, which kicks off on Friday, comes amid increasingly dire warnings by the International Monetary Fund, among others, of the potential harm faced by the world economy from Mr Trump's trade wars.
Britain and Argentina went to war over the Falkland/Malvinas islands in 1982, and May will be the first British leader to visit the Argentine capital.