NEW YORK — The Dow Jones Industrial Average plunged more than 600 points Friday after the latest escalation in the trade war between the U.S. and China rattled investors. The broad sell-off sent the S&P 500 to its fourth straight weekly loss.

Stocks tumbled after President Donald Trump demanded that U.S. companies with operations in China consider moving them to other countries — including the U.S. — just hours after Beijing announced new tariffs on $75 billion in U.S. goods.

Trump also announced after the market closed that the U.S. would increase existing tariffs on $250 billion in Chinese goods to 30% from 25%, and that tariffs on additional goods expected to kick in on Sept. 1 would be at 15% instead of 10%. Those announcements are likely to influence stock markets in Asia when trading opens there Monday.

Friday’s developments mark the latest escalation of an ongoing trade dispute between Washington and Beijing that has threatened the global economy and weighed on markets. The U.S. has said it would impose 10% duties on the $300 billion of Chinese goods that were not already subject to tariffs in two steps, On Sept. 1 and Dec. 15. China’s retaliatory tariffs set off the barrage of tweets from Trump that ignited a wave of selling as investors fled stocks in favor of U.S. government bonds, pushing yields higher. The price of gold also rose.

“The market is spooked by the escalation in the trade war,” said Janet Johnston, portfolio manager at TrimTabs Asset Management. “Investors are looking for an endgame and we haven’t seen it yet.”

The S&P 500 fell 75.84 points, or 2.6%, to 2,847.11. The index is now down 4.5% for the month. It’s still up 13.6% for the year.

The Dow lost 623.34 points, or 2.4%, to 25,628.90. The average briefly dropped 745 points. The Dow has had five declines of 2% or more this year, with three of them coming this month.

The Nasdaq gave up 239.62 points, or 3%, to 7,751.77. The Russell 2000 index of smaller company stocks skidded 46.52 points, or 3.1%, to 1,459.49.

Trump also said Friday morning that he was “ordering” UPS, Federal Express and Amazon to block any deliveries from China of the powerful opioid drug fentanyl. The stocks of all three companies fell as traders tried to assess the possible implications.

Matt Arnold, an analyst who covers FedEx and UPS for Edward Jones, said it could be difficult for the companies to comply should the administration draft detailed guidelines for rooting out fentanyl.

“There are just too many instances in which the package contents can’t be known or verified,” he said. “It’s difficult to picture a scenario where UPS and FedEx are all that well-equipped to detect something like this.”

Technology companies, which have much to lose in the trade battle, bore the brunt of the sell-off. Apple slid 4.6% and Microsoft gave up 3.2%. Chipmaker Nvidia dropped 5.3%.

Companies that rely on consumer spending also took losses. Retailer L Brands plunged 9.3%.