After a week of hints and uncertainty, President Donald Trump said Thursday he would announce tariffs on imported steel and aluminum but with temporary exemptions for Canada and Mexico as he seeks to revise the North American Free Trade Agreement. He suggested Australia and "other countries" might also be spared, a shift that could soften the international blow amid threats of retaliation by trading partners.

Trump's tariffs on steel and aluminum imports will take effect in 15 days, with Canada and Mexico indefinitely exempted from the duties, according to people outside the White House who were briefed on the plans Thursday. The people spoke on condition of anonymity ahead of the president's signing of the orders.

"We're going to be very fair, we're going to be very flexible but we're going to protect the American worker as I said I would do in my campaign," Trump said during a Cabinet meeting.

The president reiterated that he would levy tariffs of 25 percent on imported steel and 10 percent on aluminum but would "have a right to go up or down depending on the country and I'll have a right to drop out countries or add countries. I just want fairness."The president indicated Canada and Mexico's treatment would be connected to the ongoing NAFTA talks, which are expected to resume in early April.

The people briefed on the plans said all countries affected by the tariffs would be invited to negotiate with the Trump administration to be exempted from the tariffs if they can address the threat their exports pose to U.S. manufacturers. The people said the exclusions for Canada and Mexico could be ended if talks to renegotiate NAFTA stall.

The process of announcing the penalties has been the subject of an intense debate and chaotic exchanges within the White House, pitting hard-liners against free trade advocates such as outgoing economic adviser Gary Cohn aiming to add more flexibility for U.S. trading partners.

The fight over tariffs comes amid intense turmoil in the West Wing, which has seen waves of departures and negative news stories that have left Trump increasingly isolated in the Oval Office, according to two senior officials speaking on the condition of anonymity to discuss internal thinking. Trump was still hearing last-minute pleas from opponents of the tariff plan, and White House officials said they couldn't predict how the day would shake out.

Steel and aluminum workers were invited to the White House for the afternoon announcement with Trump.

Congressional Republicans and business groups are bracing for the impact of the tariffs and the departure of Cohn, a former Goldman Sachs executive who has opposed them.

House Speaker Paul Ryan, appearing at a session with Home Depot employees in Atlanta, said ahead of Trump's announcement, "I'm just not a fan of broad-based, across-the-board tariffs." He pointed to the store's many products that rely on steel and aluminum.

More than 100 House Republicans wrote Trump on Wednesday, asking him to reconsider "the idea of broad tariffs to avoid unintended negative consequences" to the U.S. economy and workers.

Arizona Sen. Jeff Flake, a Republican, said he plans to introduce legislation next week to nullify the tariffs though he has acknowledged that finding the votes to stop the president's actions could be difficult.

Business leaders, meanwhile, continue to sound the alarm about the potential economic fallout from tariffs, with the president and CEO of the U.S. Chamber of Commerce raising the specter of a global trade war. That scenario, Tom Donohue said, would endanger the economic momentum from the GOP tax cuts and Trump's rollback of regulations.

"We urge the administration to take this risk seriously," Donohue said.

The president has said the tariffs are needed to reinforce lagging American steel and aluminum industries and protect national security. He has tried to use the tariffs as leverage in ongoing talks to renegotiate NAFTA, suggesting Canada and Mexico might be exempted from tariffs if they offer more favorable terms under the trade agreement.

AP