Neither country mentioned auto tariffs in their official briefings of the meeting on Saturday.
But Mnuchin said, "I think there's no question the president's tariff strategy has worked". But if not remember ... I am a Tariff Man.
On Monday, Kudlow said there was an "assumption" that China would eliminate auto tariffs, not a specific agreement.
A US government official briefed on the matter told Reuters on Monday that no final report on the investigation is expected for at least a couple of weeks.
Beijing and Washington now have 90 days to make progress in talks over the main issues, which include U.S. complaints that China forces American companies to hand over technology and steals their intellectual property through hacking.
As investors confronted uncertainty, markets had one of their worst trading days of the year.
The Dow Jones Industrial Average shed 3.1% while the tech-dominated Nasdaq was nearly 4% down by the close.
The S&P 500 posted 44 new 52-week highs and 1 new low; the Nasdaq Composite recorded 73 new highs and 81 new lows.
The Trump administration raised doubts Tuesday about the substance of a U.S.
For their part, Trump and White House officials have promoted the apparent US-China agreement in Buenos Aires as a historic breakthrough that would ease trade tensions and potentially reduce tariffs - even though Beijing has not confirmed that it made most of the concessions that the Trump administration has claimed.
Amid the renewed tensions over tariffs, Mr. Trump held an unusual meeting at the White House with Germany's three largest automakers - Volkswagen, Daimler and BMW - seeking increased investment in their US facilities. VW CEO Herbert Diess is also planning to attend, a person briefed on the matter said. He said it could include VW using unused Ford capacity to build cars. Daimler CEO Dieter Zetsche will be in attendance as well, Daimler said. "It will now be considered a 'controlled substance,"' Trump said in another tweet Wednesday, subsequently adding that China would see "incredible" results if it imposed the death penalty on "distributors and pushers". The European Union warned that it would retaliate with tariffs on USA products.
Kudlow, director of the National Economic Council, said he, Mnuchin and U.S. Trade Representative Robert Lighthizer held private meetings in Argentina with China's Vice Premier Liu He, who told them Beijing would move quickly on its new commitments.
Mr. Ross asked the German vehicle manufacturers to increase production in America.
Be patient, said Ma Hong, a trade expert at Tsinghua University in Beijing. A senior BMW AG executive is also expected to attend. The administration has threatened to cut off government subsidies for electric cars in retaliation.
Tigress Financial analyst Ivan Feinseth said Xi is starting to feel the trade war heat and may be more motivated to negotiate than he was in the past.
White House economic adviser Larry Kudlow said on Tuesday that a reduction in Chinese tariffs on US cars and agricultural and energy commodities would be a "litmus test" for whether U.S.
Goldman Sachs analyst Alec Phillips said the US and China made little concrete progress at G20, which was what he anticipated heading into the meeting.
Trump had tweeted Sunday that China agreed to "reduce and remove" its 40 percent tariff on cars imported from the U.S. Mnuchin said Monday that there was a "specific agreement" on the auto tariffs. But both leaders face a mix of economic nationalists, free trade advocates and other conflicting forces at home.