Trader Ryan Falvey works on the floor of the New York Stock Exchange on Thursday. The markets remain jittery as investors braced for a crucial phase in U.S.-China trade negotiations. (Richard Drew/AP)

Stocks continued their week-long turbulence Thursday, with the Dow Jones industrial average tumbling more than 400 points, then rebounding, on deepening concerns that a U.S.-China trade deal may be on the verge of collapse.

The Standard & Poor’s 500 index retreated as much as 1.4 percent, and the Nasdaq composite was down 1.8 percent in morning trading. But stocks clawed back after President Trump said at the White House that a deal was still possible and that he had received “a beautiful letter” from Chinese President Xi Jinping.

The Dow closed the day at 25,828, a loss of 139 points, or 0.53 percent. The S&P 500 fell 8.7 points, or 0.30 percent, to finish at 2,870. The Nasdaq Composite was off 32.73 points on the day, about 0.41 percent, and closed at 7,910.

Real estate was the only industry out of 11 S&P sectors to finish the day in positive territory.

Asian stocks were down overnight, with Japan’s Nikkei 225 retreating nearly 1 percent and Hong Kong’s Hang Seng down 2.4 percent. The Shanghai composite was feeling pressure, too, sliding nearly 1.5 percent.

Europe closed in the red. France’s CAC 40 dropped 1.9 percent. Germany’s DAX was down 1.7 percent, and England’s FTSE 100 was off less than 1 percent.

Markets were bracing for a crucial phase in the negotiations between the United States and China. President Trump has said he will raise tariffs on Chinese goods starting early Friday.

Thursday night in Florida, Trump said that China “broke the deal” in the ongoing trade talks. “They can’t do that, so they’ll be paying,” he told supporters at a rally in Panama City Beach.

Twenty-one of the 30 Dow blue chips were in the red. The big gainer on the day was Chevron, which climbed 3.2 percent, followed by Dow and Goldman Sachs. Chevron pocketed a $1 billion breakup fee after it dropped its pursuit of Anadarko Petroleum, allowing Occidental Petroleum a clear path to acquiring the shale-oil company.

“Lots of broken hearts today,” said analyst Jennifer Rowland of Edward Jones. “Chevron and Anadarko break up, and market is jittery about U.S. and China breaking up trade deal.”

Intel, 3M, Apple and Disney were the hardest-hit Dow stocks in afternoon trading. Nasdaq stocks also took a beating, with chipmaker Microchip Technology, NVIDIA and the FAANG group — Facebook, Amazon, Apple, Netflix and Google-parent Alphabet — under siege.

Facebook co-founder Chris Hughes called Thursday for a breakup of the company, saying fellow co-founder Mark Zuckerberg was “not accountable.” Facebook shares ended at $188.65, down 0.47 percent on the day.

The week’s volatility was ignited by tweets last weekend from Trump, who threatened to increase tariffs from 10 percent to 25 percent on $200 billion worth of Chinese goods on Friday. He also said a new 25 percent fee on all remaining Chinese imports would follow “shortly” thereafter. The surprise move jeopardized talks that appeared headed for a deal.

After markets closed Monday, senior Trump administration officials accused Beijing of “reneging” on commitments made earlier in trade talks and reaffirmed their plan to raise tariffs.

Both sides were trying to repair the damage and conclude some sort of deal that is in the interest of the two biggest economies in the world.

Chinese Vice Premier Liu He was expected to meet U.S. Trade Representative Robert E. Lighthizer on Thursday, just hours before the higher levies kick in. The Chinese delegation is “coming to the U.S. to make a deal,” Trump tweeted. “We’ll see.”

The three major U.S. indexes had been near all-time highs last Friday, with the Dow up 12 percent for the year, the S&P 500 up more than 15 percent and the Nasdaq ahead 20 percent.

Analysts said markets can get over this week’s bump and continue marching upward if trade peace is achieved.

“We continue to believe that in order for the S&P 500 to sustain new record highs, we need a trade deal and stabilization in the global economy,” said Scott Wren of the Wells Fargo Investment Institute. “Those two concepts are closely tied.”