The Dow Jones industrial average posted the biggest drop in points, 724, since the 2008 financial crisis as President Trump's tariffs on Chinese imports fueled growing fears of a trade war that could wipe out the economic gains under his administration.

While the drop was smaller in relative terms than those of a decade ago, reflecting the subsequent surge in the blue-chip index's value, investors predict more to come, with China promising to fight "to the end" in any trade war. The broader S&P 500 slid 2.5 percent, and the tech-heavy Nasdaq Composite Index fell 2.4 percent.

"Buckle your seat belts," said Greg McBride, chief financial analyst for Bankrate.com. "At a time when interest rates are rising, central banks are beginning to withdraw stimulus from markets and the odds of a trade war have grown, you can bet that markets will be volatile. Expect more of these ups and downs."

The president's plan for trade restrictions with China, outlined in a memo Trump signed Thursday, involves duties of 25 percent on goods in sectors such as aerospace, information communication technology, and machinery. His trade chief, Robert Lighthizer, has about two weeks to determine which items, specifically, should be included in the levies, which may have a combined value of $60 billion.

A comment period after Lighthizer's recommendations would extend for at least a month, giving Wall Street time to express its concerns about a trade war between the two biggest economies on the planet.

"Unilaterally imposing tariffs or other restrictions without a long-term strategy to bring about reforms in China will only raise prices in America, make American companies and products less competitive, and harm U.S. workers and consumers," the Business Roundtable, which represents the 200 largest U.S. companies, said Thursday.

The group recommended that the White House instead pursue a more comprehensive strategy of consulting allies to identify trade barriers in China, setting deadlines for President Xi Jinping to remove them and outlining actions the U.S. would take if those timetables aren't met.

Trump, who said talks with China are ongoing, is nonetheless confident that his actions will yield positive results. "We’re doing things for this country that should have been done for many, many years," he said in a signing ceremony at the White House. "We’ve had this abuse by many other countries and groups of countries that were put together in order to take advantage of the United States, and we don’t want that to happen. We’re not going to let that happen."

China's embassy in Washington, meanwhile, described the administration's moves as "self-defeating" in a statement on Thursday afternoon. The country "has made great efforts to address the current trade imbalance between China and the U.S.," the embassy said. "China does not want a trade war with anyone, but China is not afraid of, and will not recoil from, a trade war."

Fears that Trump would ignite such a conflict have been growing since his decision to impose tariffs of 25 percent on steel imports and 10 percent on aluminum under national security provisions of federal law. The duties announced Thursday involve unfair trade practices, a different section of the law, but the White House has wide latitude under both.

“The core point in trying to understand what the administration is doing,” said Robert Zoellick, a trade adviser under former Preisdent George W. Bush, is that Trump, Lighthizer and Commerce Secretary Wilbur Ross have long believed that trade deficits “are like negative net income for a businessperson. It’s losing.”

Facing an imbalance between exports and imports that grew to $568.4 billion last year, the administration “is trying to change the outcome,” Zoellick, the nonexecutive chairman at Alliance Bernstein and a previous head of the World Bank, told an international gathering in Brussels earlier this month.

Economists have cautioned that trade imbalances aren't necessarily bad -- particularly in a consumer-driven economy like that of the U.S., where personal consumption accounts for nearly 70 percent of gross domestic product.

Trump's decades-long protectionist beliefs, however, have left Wall Street worried that more such policies are in the works, and retailers -- who make up $2.6 trillion of the U.S. economy, or more than a tenth -- fear his renegotiation of the North American Free Trade Agreement will disrupt their supply chains.

Worse, if the tariffs spark a global trade war, that could wipe out much of the growth from the president's loosening of regulations and a GOP-led tax cut that slashed the top corporate to 21 percent from 35 percent.

“Middle and working-class Americans are just starting to see the benefits of tax reform in the form of bigger paychecks and higher wages," National Retail Federation CEO Matthew Shay said Thursday. "A trade war will erase those gains and result in higher prices for a wide range of consumer products and basic household goods. And the tariffs will create uncertainty for retailers and other businesses who are prepared to reinvest savings from the tax cut."

Republicans, who control both houses of Congress, have expressed repeated concerns about Trump's trade stances. Sen. Pat Roberts of Kansas, a state dominated by the agriculture industry, warned Lighthizer during a hearing Thursday that his state's farmers need the government's support, and Chuck Grassley of Iowa said his state "stands to lose a great deal from retaliation" if China responds by placing duties on U.S. crops.

"Agriculture is going to be a big loser here if this goes down the road we're going down," said Sen. Claire McCaskill, a Missouri Democrat, who noted that Canada, Mexico and China are among the top importers of her state's crops.

"It is really worrisome to an economy dependent on agriculture that we’re going to say, 'Well, it’s for the national good and you guys are just going to have to power through it,'" she said.

