trade talks china trade war devalue dollar peter navarro aman _00000000.jpg
trade talks china trade war devalue dollar peter navarro aman _00000000.jpg
Now playing
18:55
Navarro: US has 'structural' problems with China
American flags hang oustside of the New York Stock Exchange Tuesday, Feb. 16, 2021, in New York. (AP Photo/Frank Franklin II)
PHOTO: Frank Franklin II/AP
American flags hang oustside of the New York Stock Exchange Tuesday, Feb. 16, 2021, in New York. (AP Photo/Frank Franklin II)
Now playing
01:31
Rising bond yields trigger Wall Street sell-off
WASHINGTON, DC - FEBRUARY 01: U.S. President Joe Biden (Center R) and Vice President Kamala Harris (Center L) meet with 10 Republican senators, including Mitt Romney (R-UT), Bill Cassidy (R-LA) and Susan Collins (R-ME), in the Oval Office at the White House February 01, 2021 in Washington, DC. The senators requested a meeting with Biden to propose a scaled-back $618 billion stimulus plan in response to the $1.9 trillion coronavirus relief package Biden is currently pushing in Congress. (Photo by Doug Mills-Pool/Getty Images)
PHOTO: Pool/Getty Images North America/Getty Images
WASHINGTON, DC - FEBRUARY 01: U.S. President Joe Biden (Center R) and Vice President Kamala Harris (Center L) meet with 10 Republican senators, including Mitt Romney (R-UT), Bill Cassidy (R-LA) and Susan Collins (R-ME), in the Oval Office at the White House February 01, 2021 in Washington, DC. The senators requested a meeting with Biden to propose a scaled-back $618 billion stimulus plan in response to the $1.9 trillion coronavirus relief package Biden is currently pushing in Congress. (Photo by Doug Mills-Pool/Getty Images)
Now playing
02:08
Zandi: Stimulus plan doesn't do enough for the most in need
Now playing
01:36
Michael Bolton wants you to break up with Robinhood
Now playing
03:02
Congressman: The stock market needs to protect retail investors
Now playing
03:51
GameStop investor on why he's still holding on
why it
why it's better to invest cash than save it kristen bitterly orig_00012028.png
Now playing
01:59
Holding onto your cash? History shows it's better to invest it
In this photo provided by the New York Stock Exchange, Michael Urkonis, center, works with fellow traders on the floor during the Signify Health IPO, Thursday, Feb. 11, 2021. Stocks edged higher on Wall Street in early trading Thursday as investors continued digesting solid corporate earnings reports and maintained confidence that a new round of government aid is on the horizon. (Courtney Crow/New York Stock Exchange via AP)
PHOTO: Courtney Crow/AP
In this photo provided by the New York Stock Exchange, Michael Urkonis, center, works with fellow traders on the floor during the Signify Health IPO, Thursday, Feb. 11, 2021. Stocks edged higher on Wall Street in early trading Thursday as investors continued digesting solid corporate earnings reports and maintained confidence that a new round of government aid is on the horizon. (Courtney Crow/New York Stock Exchange via AP)
Now playing
03:08
El-Erian on risks to the market rally
PHOTO: Courtesy Kearns family
Now playing
02:56
Parents of young trader who died by suicide: Robinhood is to blame
kenny polcari market overvalued and stretched orig_00013830.png
kenny polcari market overvalued and stretched orig_00013830.png
Now playing
02:32
Polcari: A healthy market pullback of 5-7% should happen
Bitcoin
PHOTO: CNN
Bitcoin
Now playing
03:17
Tesla invests $1.5 billion in bitcoin
Now playing
02:20
El-Erian: Robinhood is a reminder that 'you have no friends on Wall Street'
People walk by a GameStop store in Brooklyn on January 28, 2021 in New York City. Markets continue a volatile streak with the Dow Jones Industrial Average rising over 500 points in morning trading following yesterdays losses. Shares of the video game retailer GameStop plunged. (Photo by Spencer Platt/Getty Images)
PHOTO: Spencer Platt/Getty Images
People walk by a GameStop store in Brooklyn on January 28, 2021 in New York City. Markets continue a volatile streak with the Dow Jones Industrial Average rising over 500 points in morning trading following yesterdays losses. Shares of the video game retailer GameStop plunged. (Photo by Spencer Platt/Getty Images)
Now playing
01:17
Here's why GameStop shares are plunging
PHOTO: CNN
Now playing
02:22
His risky bet made him a millionaire on paper. It could've gone very differently
NEW YORK, NEW YORK - JANUARY 27: GameStop store signage is seen on January 27, 2021 in New York City. Stock shares of videogame retailer GameStop Corp has increased 700% in the past two weeks due to amateur investors. (Photo by Michael M. Santiago/Getty Images)
PHOTO: Michael M. Santiago/Getty Images
NEW YORK, NEW YORK - JANUARY 27: GameStop store signage is seen on January 27, 2021 in New York City. Stock shares of videogame retailer GameStop Corp has increased 700% in the past two weeks due to amateur investors. (Photo by Michael M. Santiago/Getty Images)
Now playing
03:16
GameStop mania shakes up Wall Street
Now playing
05:26
Christine Romans: This is being fueled by the elixir of a quick profit
(CNN Business) —  

US oil prices collapsed Thursday after President Donald Trump fired another shot in the US-China trade war.

Trump’s vow to impose a 10% tariff on another $300 billion of US imports from China is worrying investors that a severe economic slowdown could eat into demand for oil and other commodities. The escalation also raises the risk that China will retaliate by imposing tariffs on US oil.

Crude tumbled 8% to $53.95. That’s the biggest single-day decline since February 2015. Oil was already in the red prior to Trump’s tweet, which then accelerated those losses.

“This is heightening fear of a major slowdown,” said Ryan Fitzmaurice, energy strategist at Rabobank.

US stocks and Treasury bond yields also fell sharply on the news, underscoring the worry on Wall Street.

Investors were already on high-alert for signs of weakness in the economy, especially after the Federal Reserve lowered interest rates this week for the first time in nearly 11 years.

“Prices were weak prior to the tweet. And then once it came out, it really snowballed,” Fitzmaurice said.

Earlier on Thursday, the Institute for Supply Management said American manufacturing activity tumbled in July to the weakest level in nearly three years. Economists had anticipated a slight improvement in factory activity.

China, the world’s No. 2 economy, has gone easy on US oil in the trade war by declining to impose tariffs on crude. However, that could change if the trade war deepens because Beijing has all but run out of US products to tariff.