Some key events in Canada-U.S. trade relations since 2017:

Aug. 16, 2017 - Canada, Mexico and the United States commence the renegotiation of the North American Free Trade Agreement, which U.S. President Donald Trump had called “the worst trade deal in history” while campaigning for the role in 2016.

March 14, 2018 - Prime Minister Justin Trudeau says Canada won't be “bowled over” at the NAFTA talks by Trump. Trudeau makes the remarks while visiting steelworkers in Sault Ste. Marie, Ont.

May 31, 2018 - The U.S announces tariffs of 25 per cent on imports of Canadian steel and 10 per cent on aluminum to take effect the next day. Lack of progress in NAFTA renegotiations was cited by Washington as the reason for the tariffs.

In retaliation, Canada later the same day announces plans to impose taxes of up to $16.6 billion on steel, aluminum and hundreds of other products from the United States.

June 7, 2018 - Trump hurls a series of personal insults at Trudeau from Air Force One after a G7 summit meeting in Quebec. The president calls Canada's prime minister “dishonest” and “weak” after Trudeau repeated his objections to massive steel and aluminum tariffs.

Aug. 27, 2018 - Mexico and the United States announce their own bilateral trade deal after weeks of negotiations that were supposed to be specific to the automotive industry. Foreign Affairs Minister Chrystia Freeland cancels a trip to Europe and diverts to Washington, D.C., starting a month of intense negotiations to bring Canada into the agreement.

Sept. 30, 2018 - Trump's and Trudeau's teams work out last minute details that bring Canada into a renewed continental trade pact.

Oct. 1, 2018 - Trump declares victory on a renewed NAFTA in Washington, D.C. The president refuses to be pinned down on whether he intends to ease tariffs on Canadian exports of steel and aluminum.

Nov. 30, 2018 - Prime Minister Justin Trudeau and his counterparts from the United States and Mexico sign a new three-way trade agreement in Buenos Aires, on sidelines of a meeting of G20 countries, in spite of continued U.S. tariffs on steel and aluminum.

Dec 18, 2018 - Foreign Affairs Minister Chrystia Freeland says Donald Trump's steel and aluminum tariffs contradict what was negotiated in the new North American Free Trade Agreement.

May 17, 2019 - Canada and the U.S. reach an agreement that ends the 25 per cent tariff on steel and 10 per cent levy on aluminum. Canada had said the measures stood in the way of ratifying the new NAFTA agreement.

Oct. 30, 2019 - A U.S. watchdog criticizes the way the Trump administration handles taxes on imported steel and aluminum, saying a lack of transparency on the tariffs imposed in March 2018 creates the appearance of “improper influence.”

July 1, 2020 - The United States-Mexico-Canada Agreement, an update to the North American Free Trade Agreement in place since 1994, takes effect.

July 8, 2020 - Presidents of the United States and Mexico meet at White House to celebrate new North American trade deal. Trudeau declined Trump's invitaton, citing the challenges from the COVID-19 pandemic and parliamentary business.

July 13, 2020 - Prime Minister Justin Trudeau urges President Donald Trump to think twice before imposing new tariffs on Canadian aluminum.

Aug. 6, 2020 - U.S. President Donald Trump announces plans to reimpose a 10-per-cent tariff on Canadian aluminum, saying “Canada was taking advantage of us, as usual.” The tariff had previously been imposed in 2018 and suspended in 2019.

Deputy prime minister Chrystia Freeland, who played a pivotal role in negotiating with the United States as foreign minister, issues official statement saying Canada would swiftly impose countermeasures on a “dollar-for-dollar basis.”

Aug. 7, 2020 - Freeland says Canada will hit back with $3.6 billion in tariffs of its own. She says the government will consult with the domestic industry to determine which items to target. She says the goal is to inflict the least damage on Canada and the “strongest possible impact” on the United States.

Ontario Premier Doug Ford, who has voiced support for Trump in the past, accused the president of slapping the Canadian public in the face with the renewed tariffs. “We will come back swinging like they've never seen before,” Ford says.

- With files from The Associated Press