USA employment data released Friday were in line with expectations but Trump's threat Thursday of new tariff hikes on Chinese goods "renders backward-looking data comfort irrelevant", said Varathan of Mizuho Bank.
The yuan broke through 7 to the USA dollar on Monday after the People's Bank of China set its daily reference rate weaker than 6.9 for the first time since December.
"China dropped the price of their currency to an nearly a historic low", Trump said in a tweet. It's called 'currency manipulation.' Are you listening Federal Reserve?
China's central bank sets the yuan's exchange rate each morning and allows it to fluctuate by two per cent against the dollar during the day.
Trump has repeatedly complained that China hasn't made the "large quantities" of agricultural purchases that he claims President Xi Jinping promised when they met in Osaka at the G-20 summit.
Accordingly, investors should watch for the next developments in the US-China trade dispute as it will drive the stock market in the near future.
The dollar has gained 2.2 percent against the yuan since Trump's pledge on Thursday to put a 10 percent tax on $300 billion of Chinese imports, the USA currency's biggest move in nearly exactly four years.
South Korea's won extended a decline to a three-year low Monday after breaching the key 1,200 support level.
But this significant downturn is an answer to "unilateralism and trade-protectionist measures" and the latest round of impending tariffs, according to a statement from the People's Bank of China. Other are saying that suggests the move represents China's commitment to a long, drawn-out trade war.
It went on to say that it had the "experience, confidence and ability to keep the RMB exchange rate basically stable at a reasonable and balanced level".
The weakness of the yuan, also known as the renminbi, or "people's money", is among US grievances against Beijing.
CURRENCY: The dollar dropped to 105.93 yen from Friday's 106.59 yen.
"This means that some of the tariff costs to United States consumers will be offset by such devaluation of the Chinese currency, and that Chinese exporters will get less revenue in their local currency for their dollar sales in the USA", said Ed Yardeni, president of Yardeni Research.
The level of seven yuan to the dollar has no economic significance, but could revive USA attention to the exchange rate.
"Trade continues to trend in the wrong direction".
They've also forced down markets worldwide as investors brace for volatility amid the trade tensions. Trump is also eyeing tariffs on the European Union, but has yet to make a formal announcement. The offshore yuan sank as much as 1.9% to a record low.
Asian shares suffered their steepest daily drop in 10 months, with MSCI's broadest index of Asia-Pacific shares .MIAPJ0000PUS outside Japan sinking 2.5% to depths not seen since late January. Trade bellwethers Caterpillar and Boeing were down 2 percent.
Corn and soybean futures fell after Bloomberg News reported that China's state-run agricultural firms have stopped buying American farm goods, and are waiting to see how trade talks progress.
At 9:50 a.m. ET, the Dow Jones Industrial Average was down 505.65 points, or 1.91%, at 25,979.36, the S&P 500 was down 59.19 points, or 2.02%, at 2,872.86.