Trump's comments point to a willingness to push the envelope as far as the US needs to get Chinese tariff concessions, along with a pledge to stop allegedly stealing American technology. Losses over the past three months have reached almost 8% amid a global trade spat and concerns over an economic slowdown in China.
The pan-European FTSEurofirst 300 index lost 0.20 percent, as shares of France's Publicis tumbled after its report.
He said: "China, the European Union and others have been manipulating their currencies and interest rates lower, while the USA is raising rates while the dollars gets stronger and stronger with each passing day - taking away our big competitive edge".
"Currency is now part of the trade war, folks", said Greg McKenna, market strategist at AxiTrader.
It is also unusual for a president to openly critique monetary policy, though Trump said he is not concerned by perceptions that his comments could compromise the Fed's independence. But it's something investors will have to think about.
"Look, I'm not doing this for politics", Trump said in the interview.
The S&P 500 index dipped 2.66 points, or 0.1 percent, to 2,801.83. The Nasdaq composite fell 1 point to 7,824. The dollar fell and bond yields rose.
Brent crude futures rose 0.9 percent to $73.24 a barrel, maintaining their gains so far this week, after Saudi Arabia's OPEC governor said the kingdom's exports are likely to fall next month and inventories may be squeezed in the third quarter. JPMorgan Chase gained 1.1 percent to $111.11 and Bank of America picked up 1.4 percent to $30.07.
The dollar dropped sharply, to 111.52 yen from 112.46 yen.
"There's no question that the weakening of the currency creates an unfair advantage for them", Mnuchin said. The Russell 2000 index of smaller-company stocks was little changed at 1,702.
US President Donald Trump said in an interview released today he is willing to hit all Chinese goods imported to the United States with tariffs if necessary.
Earlier this month, the United States imposed tariffs on $34 billion of Chinese imports. return, China levied taxes on the same value of U S products. And last week, the administration announced plans for yet more tariffs on $200 billion worth of additional Chinese imports.
Worries about a full-blown global trade war are likely to persist as officials from the EU Trade Commission, due to arrive in Washington next week for trade talks, are said to be preparing a list of retaliatory measures in response to proposed US tariffs on European Union cars.
Trump's latest move in the trade war with China came as investors try to gauge the ability of the Asian nation's economy - the world's second-biggest - to withstand a protectionist showdown.
But Trump's comments did not do much to push the dollar down versus the yuan, however. If the yuan continues to depreciate, goods exported to China will become more expensive to consumers there and Chinese exports would also be relatively cheaper.
Wall Street is becoming increasingly immune to Donald Trump's headline-grabbing behaviour.