Optimism that Beijing and Washington will eventually hammer out a partial agreement as part of a wider deal has supported equities for weeks, helping Wall Street to numerous records.
But investor sentiment was dealt a blow on Monday when Donald Trump said he would reinstate steel and aluminium tariffs on the two South American countries, which he accused of manipulating their currencies and hurting US farmers.
Later, officials warned they would hit France with up to 100% in levies on US$2.4bil in goods, saying a digital tax was discriminatory against US tech firms such as Google, Apple and Amazon.
Sparkling wine, yoghurt and Roquefort cheese could be hit as soon as next month, while US Trade Representative Robert Lighthizer warned his office was also considering similar moves against Austria, Italy, and Turkey.
On Tuesday, France vowed a "strong" response to any sanctions.
"Given Brazil was seen as a close friend of Trump and even they could not be exempt from tariffs, there is a notion that every country, regardless of what they do, could have tariffs imposed, which creates a lot of uncertainty of businesses," said Tapas Strickland at National Australia Bank.
Analysts said the moves against Brasilia and Buenos Aires citing currency movements raised the possibility the US could use a similar justification against China, which it has also accused of forex manipulation.
Adding to the sense of unease, US Commerce Secretary Wilbur Ross told Fox News that more tariffs on Chinese goods planned for December 15 would be imposed if the first phase of trade talks was not completed by then.
"If nothing happens between now and then, the president has made quite clear he'll put the tariffs in," he said.
Tokyo ended 0.6% lower, Hong Kong shed 0.2% and Sydney sank more than 2% with investors disappointed that the Australian central bank held off cutting interest rates.
Seoul retreated 0.4% and Singapore was off 0.6% while Manila eased 0.2%. Mumbai, Taipei and Jakarta were also down but Shanghai and Taipei both ended with small gains.
In early trade London fell 0.1% but Frankfurt jumped 0.7% and Paris gained 0.2%.
Still, JP Morgan Asset Management strategist Kerry Craig said there were expectations that a "narrow deal around trade can be achieved".
But he added: "While there is a clear economic incentive from both sides to do some sort of deal, the political desire to reach more than the minimum is weak, as the two sides are still going to want to compete in areas such as technology."
The uncertainty over trade, combined with a disappointing US manufacturing report, sent all three main indexes on Wall Street tumbling, while Paris and Frankfurt also suffered big losses.
On forex markets, the yen, considered a safe haven in times of uncertainty, rallied higher on Monday against the dollar but pared its gains in early Asian business.
Oil prices extended gains ahead of a key meeting of OPEC and other major producers, which is expected to see them maintain output cuts into June, with speculation they could go on until the end of 2020. - Agencies
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