– President Donald Trump demanded U.S. companies stop doing business with China and announced increased tariffs on Beijing on Friday, capping one of the most extraordinary days in the long-running U.S.-China trade war.

By the end of the trading day, the Dow Jones industrial average had fallen 600 points, or nearly 2.4%, and the business community was warning of negative effects on investor confidence and American jobs.

The day began with Beijing's announcement that it would levy new tariffs on $75 billion in goods, including reinstated levies on auto products, starting this fall.

Beijing's tariff retaliation was delivered with strategic timing, hours before an important address by the Fed chair, Jerome Powell, and as Trump prepared to depart for the Group of Seven summit in Biarritz, France.

Trump initially directed his ire at Powell in Friday tweets, painting the Fed's lack of monetary easing as a greater threat to American workers and businesses. "My only question is, who is our bigger enemy, Jay Powell or Chairman Xi?" he tweeted.

But moments later, he said he would be responding to China's tariffs later Friday and demanded American companies cut ties with China.

"Our great American companies are hereby ordered to immediately start looking for an alternative to China, including bringing your companies HOME and making your products in the USA," Trump tweeted.

The White House does not have the authority to force companies to follow such directives, and Trump's demand came under sharp criticism from the U.S. business community, which warned that halting sales with such a large trading partner would hurt American companies and the broader economy.

"Trump may be frustrated with China, but the answer isn't for U.S. companies to ignore a market with 1.4 billion consumers," said Myron Brilliant, executive vice president at the U.S. Chamber of Commerce. "Escalating tensions is not good for market stability, investor confidence or American jobs."

Late Friday afternoon, Trump tweeted that he would be raising the tariff rates on some $250 billion in Chinese goods from 25% to 30%. The president also tweeted that he would increase the tariff rate on an additional $300 billion of Chinese goods that are not yet under tariff.

Business lobbyists scrambled throughout the day on Friday to get answers about the White House's plans for retaliation, but many administration advisers were either in transit on their way out of the country to the G-7 meeting or already in France, according to two senior industry officials who spoke on the condition of anonymity.

Business interests have been cautious not to denigrate Trump's trade moves with China too strongly, eager to support the president's goals of fairer trade practices and maintain a bridge to the administration.

But the president's stunning new directive for U.S. companies to sever ties to China likely represents a new risk that could lead to more dire warnings and intense criticisms of the administration, these officials said, particularly for large U.S. multinational corporations that have for years been planning to try to benefit from the growing Chinese consumer market.

"I have no idea how the president thinks he can order companies to stop working with China. I'm baffled," said Brian Riedl, a budget expert at the Manhattan Institute, a conservative think tank.

Senior Republicans on Capitol Hill were in the dark as of Friday afternoon about the administration's plans, according to two GOP aides who spoke on the condition of anonymity.

While dozens of major companies including Google and Nintendo have already shifted supply chains out of China, most are rebuilding them abroad, primarily in Southeast Asia.

Trump's attacks could put him under intense pressure at the G-7 summit, where he has called a special session to discuss the global economy. He has repeatedly lauded the nation's economic prowess, while saying economies elsewhere in the world are in trouble.

But the U.S. economy's performance is much more intertwined with global pressures than Trump has acknowledged, and this entanglement is forcing White House officials to decide whether they need to recalibrate Trump's approach before the 2020 election or stick with the president's impulses.

The new import taxes range from 5 to 10% and take effect Sept. 1 and Dec. 15 — the same dates Trump's latest tariffs on $300 billion in Chinese goods are slated to kick in — the Chinese finance ministry announced. A 25% tariff on automobiles and a 5% levy on auto parts go into effect Dec. 15.

"China's imposition of tariffs is a forced response to the unilateralism and trade protectionism of the United States," the Communist Party-run Global Times said. The outlet said it hoped the trade conflict would be resolved "on the premise of mutual respect and equality and trustworthiness in words and deeds."

The conflict has taken a toll across the globe. China's economic growth has slowed to its lowest rate in 27 years as factory output declines and unemployment rises. Central bank leaders in Europe, Asia and Australia have cut interest rates in recent weeks, citing the need for economic stimulus.

Sales of U.S. exports have decreased at the fastest pace since August 2009. When exports fall, manufacturers typically react by reducing inventories and cutting production, which can lead to job cuts. Air freight volumes fell nearly 5% in June, marking the eighth consecutive month of decline. Freight airlines cited the U.S.-China standoff as a prime reason for slumping demand.

American consumers have largely been shielded from the trade war's carnage, but that's poised to change. JPMorgan Chase estimated that U.S. families will absorb another $1,000 in annual costs from all Chinese tariffs after the 10% levies take hold. If the upcoming tariffs are raised to 25%, as Trump has warned, that cost jumps to $1,500, researchers estimated.

And last week, for the first time since the run-up to the Great Recession, the yields — or returns — on short-term U.S. bonds eclipsed those of long-term bonds. This phenomenon, which suggests investor faith in the economy is faltering, has preceded every recession in the past 50 years.