Wall Street ended the week with a dip in the red on Friday after a session dominated by Donald Trump's threats of a tough response to the new tariffs imposed by China.
Its flagship index, the Dow Jones Industrial Average, fell 2.37% to 25,628.90 points.
The Nasdaq, with strong technological color, plummeted 3.00% to 7.751,77 points and the expanded index S & P 500 yielded 3.00% to 2.847.11 points.
This is the fourth consecutive week of decline for the main indexes of the New York listing.
The New York Stock Exchange had started the session down, Beijing announced before the opening its intention to impose new tariffs on $ 75 billion of imports from the United States, in retaliation for additional customs duties plans to establish Washington shortly.
But the clues widened their losses after a series of threatening tweets by Donald Trump, who promised a tough response, evoking "huge sums of money stolen by China in the United States" and hammering his determination to end.
"After the retaliation measures announced by Beijing, Donald Trump has ordered US companies to find alternatives to China, which has affected big business-sensitive companies like Apple or Caterpillar," noted Schaeffer's Lillian Currens.
The apple firm, which manufactures part of its iPhones in China and sells millions of devices, lost 4.6%. That of the manufacturer of construction and construction machinery fell 3.3%.
Trump's attacks nearly eclipsed the Fed's boss's speech earlier in the day.
Jerome Powell stressed that while the US economic outlook remained favorable, trade tensions seemed "to play a role in the global slowdown and the weakness of the manufacturing sector and business investment in the United States."
In this context, the Fed chairman warned, however, that monetary policy had "no way to use" ready.
Market participants, however, expect a cut in key rates at the Fed's next monetary policy meeting on 18 September, following the July 31 cut.
In the bond market, the 2-year interest rate (1.5229%) on US debt was almost at the same level as the 10-year rate (1.5266%) around 20.20 GMT and had even exceeded briefly during the session.
A reversal of the yield curve is generally considered by analysts as an advanced sign of recession.