President Trump signaled Monday that the only way he won’t slap new tariffs on steel and aluminum imports is if a “new and fair” North American Free Trade Agreement is signed.

“Tariffs on Steel and Aluminum will only come off if new & fair NAFTA agreement is signed,” Trump tweeted.

Said Trump: “We have large trade deficits with Mexico and Canada. NAFTA, which is under renegotiation right now, has been a bad deal for U.S.A. Massive relocation of companies & jobs.”

Trump announced Thursday he plans to institute tariffs on imports of steel and aluminum this week, arguing it will level the playing field for American companies and help them expand after plant closings in recent years. The president said he decided on tariffs of 25 percent for steel and 10 percent for aluminum.

AS TARIFF BATTLE HEATS UP, TRUMP SAYS US STEEL, ALUMINUM INDUSTRIES ‘DEAD’

Amid criticism from usual Republican allies, Trump has also rebuffed U.S. allies who have pushed to be exempted from the stiff duties. While his rhetoric has been focused on China, the duties will also cover significant imports from Canada, Mexico, South Korea, Japan and the European Union.

The stock market dipped 600 points in the hours following Trump’s announcement, and businesses — including auto and boat manufacturers, the beer industry and machinery companies — were quick to denounce the move.

“Business Roundtable strongly disagrees with today’s announcement because it will hurt the U.S. economy and American companies, workers and consumers by raising prices and resulting in foreign retaliation against U.S. exporters,” Joshua Bolten, president of the influential Business Roundtable, said in a statement.

“Also, Canada must treat our farmers much better,” Trump tweeted Monday. “Highly restrictive. Mexico must do much more on stopping drugs from pouring into the U.S. They have not done what needs to be done. Millions of people addicted and dying.”

Trump’s protectionist policy will be made official in the next two weeks, White House officials said Sunday, as the administration defended the decision from critics in Washington and overseas.

Trump appeared unbowed Sunday, as he tweeted that American “Steel and Aluminum industries are dead. Sorry, it’s time for a change!”

During the presidential campaign, Trump promised to renegotiate NAFTA with Canada and Mexico, saying it has killed jobs in the United States.

Representatives from the United States, Canada and Mexico are meeting Monday for more NAFTA negotiations.

The Associated Press contributed to this report.