Updated at 9:35 a.m. | President Donald Trump did nothing to settle global markets on Friday morning, tweeting after he announced coming tariffs on imports that “trade wars are good.” And a spokeswoman said he is not concerned about a Thursday market dip that continued Friday.

The Dow Jones and other stock indexes plummeted Thursday after Trump announced he will implement the tariffs next week. And GOP lawmakers reacted quickly by warning the Republican president to pump the brakes and avoid a trade war.

European markets slipped Friday, as did ones in Asia amid panic over Trump’s tariffs announcement. U.S. markets followed suit after they opened at 9:30 a.m.

Both the Dow Jones Industrial Average and NASDAQ — along with other indexes — begin the week’s final trading day on a downward spiral. The Dow and the S&P 500 index were both down about 3 percent this week alone, part of a trend for the first two months and two days of 2018 during which American markets have lost value under Trump’s watch.

The president defended his actions Friday morning, a day after his top spokeswoman admitted he gave no thought to how U.S. trade partners might retaliate.

“When a country (USA) is losing many billions of dollars on trade with virtually every country it does business with, trade wars are good, and easy to win,” the President tweeted.

“Example, when we are down $100 billion with a certain country and they get cute, don’t trade anymore-we win big,” he wrote. “It’s easy!”

When a country (USA) is losing many billions of dollars on trade with virtually every country it does business with, trade wars are good, and easy to win. Example, when we are down $100 billion with a certain country and they get cute, don’t trade anymore-we win big. It’s easy!

— Donald J. Trump (@realDonaldTrump) March 2, 2018

Economists, national security experts and GOP lawmakers disagree with that assessment.

Trump is not concerned that global markets dipped Thursday after he announced coming tariffs on imports and endorsed a trade war, his top spokesperson said Friday. She also said the president’s top economic adviser isn’t going anywhere — for now, at least.

“No, the president’s still focused on long-term economic fundamentals,” press secretary Sarah Huckabee Sanders said. “He is incredibly focused on the American worker. It’s something that we have to have and something we need to have.”

On Thursday, Trump told reporters he will slap a “25 percent” tariff “for steel” imports and a “10 percent for aluminum.”

“And it will be for a long period of time,” he said in his typically bold fashion.

Sanders was asked if the process under which the administration must quickly put actual policy around the president’s pronouncement might change those figures.

“I wouldn’t expect those to change,” she said, according to a pool report, “but some of the other details need to be finalized.”

She also was asked about reports that Gary Cohn, the White House’s chief economic adviser, is seriously considering leaving over his opposition to the tariffs and warnings directly to Trump about their potential ramifications.

“Gary was here yesterday afternoon, I talked to him in my office several times,” Sanders said. “I don’t have any reason to think otherwise.”

In another Friday morning tweet, Trump continued to defend his promised action, particularly his long-expressed gripes about other countries steel “dumping” practices.

“We must protect our country and our workers. Our steel industry is in bad shape,” he wrote, adding: “IF YOU DON’T HAVE STEEL, YOU DON’T HAVE A COUNTRY!”

The Business Roundtable was among those on Thursday advising the president to slow down and think about the ramifications of his actions.

Joshua Bolten, its president and CEO, said in a statement the organization “shares the president’s goal of addressing global overcapacity of steel and aluminum,” but he urged Trump to “pursue other approaches that target unfair traders without putting various parts of the economy at such high risk, such as strongly enforcing U.S. unfair trade laws.”

House Financial Services  Chairman Jeb Hensarling, R-Texas, said in a statement that the “last time steel tariffs were imposed, it cost American jobs. I’m already hearing from constituents who fear this will seriously harm their businesses.”

In a telling display of the dysfunctional policy process inside the administration about the coming tarrifs, Sanders was unable to give reporters any details about the coming trade actions.