China’s retaliatory tariffs on American products caused U.S. stocks to tumble Monday on renewed fears of a trade war, as the White House vowed to fight back against Beijing’s harmful trade practices.

The Dow Jones fell 458.92 points, or 1.90 percent, after China slapped $3 billion in taxes on U.S. pork, apples and more than 100 other goods in response to the Trump administration’s tariffs on imported steel and aluminum.

The tech-heavy Nasdaq index was off 2.74 percent amid concerns about trade policy and President Trump’s continued war of words with Amazon. The tech giant was down more than 5 percent in its largest one-day point loss ever. The Nasdaq, which closed at 6,870.12, is now lower for the year.

Tensions over trade aren’t likely to ease soon. Mr. Trump is preparing to impose separate tariffs of more than $50 billion on Chinese goods after an investigation into suspected theft of U.S. intellectual property, accusations that China denies.

“The president knows that we’re billions of dollars in a trade deficit with China. He’s tired of us being taken advantage of,” said White House press secretary Sarah Huckabee Sanders. “They’ve taken our intellectual property, and the president’s going to fight back. He’s going to push back.”

China, referring to its possible response to the Section 301 investigation, said it has “yet to unsheathe its sword,” according to the official Xinhua News Agency.

Wall Street’s jittery reaction to the escalating trade feud came on the first day of work for Larry Kudlow, the president’s new head of the White House National Economic Council and a longtime critic of tariffs. Mr. Trump held a meeting of the council on Monday afternoon to discuss his economic agenda and to welcome Mr. Kudlow.

The White House said the U.S. economy “is booming under President Trump’s economic agenda,” with fourth-quarter growth in gross domestic product of 2.9 percent, unemployment at a 16-year low of 4.1 percent, and tax cuts benefiting millions of working families.

“Larry and the NEC team look forward to building on the successes of the president’s economic agenda, raising wages, and creating jobs across the country,” the White House said.

Mr. Kudlow, a former Reagan administration official, said last month that tariffs “have almost never worked as intended and almost always deliver an unhappy ending.”

The Chinese Commerce Ministry said the U.S. had violated international trade rules by imposing tariffs on steel and aluminum. China slapping tariffs in return on U.S. meat, fruit, wine and other products.

Mrs. Sanders held open the possibility that the burgeoning trade war can be resolved through negotiations; Beijing also has called for more talks with Washington.

“We want to be able to work with them to make sure that we’re getting a good deal and that we’re not taken advantage of,” she said on Fox News.

The Chinese Commerce and Finance ministries said in statements that authorities are imposing tariffs of 15 percent on 120 American products and 25 percent on eight other products, including pork and recycled aluminum.

Those products make up just a tiny portion of the hundreds of billions of dollars of goods shipped between the two countries each year. But news of the tariffs is alarming for the affected industries.

After a month of public negotiations between the U.S. and several other countries, Monday marked the first time another country has formally placed tariffs on U.S. goods in response to the Trump administration’s trade sanctions. Kate Warne, an investment strategist for Edward Jones, said China’s step is small but significant.

“The fact that a country has actually raised tariffs in retaliation is an important step in the wrong direction,” she said. “The tariffs imposed by China today lead to greater worries that we will see escalating tariffs and the possibility of a much bigger impact than investors were anticipating last week. And that could be true for Mexico as well as for China.”

The president also stepped up his criticism of Amazon, a company he blames for hurting traditional bricks-and-mortar retail businesses and costing taxpayers money through its heavy use of the U.S. Postal Service.

“Only fools, or worse, are saying that our money losing Post Office makes money with Amazon,” the president tweeted Monday. “THEY LOSE A FORTUNE, and this will be changed. Also, our fully tax paying retailers are closing stores all over the country … not a level playing field!”

The White House said last week that there were no policies for Amazon under consideration, though it is always looking for ways to even out the playing field for businesses.

⦁ This article is based in part on wire service reports.