Negotiations between the neighboring countries broke down Friday night and Ottawa said it would impose retaliatory tariffs on U.S. The United States imposed 50 per cent tariffs on US$20 billion worth of Canadian products early on Saturday and Canada immediately said it would retaliate, after last-ditch negotiations failed to resolve the latest strain in already tense relations between the historic allies. Key points and original sources are listed below.

• Negotiations between the neighboring countries broke down Friday night and Ottawa said it would impose retaliatory tariffs on U.S. goods.S1

• The United States imposed 50 per cent tariffs on US$20 billion worth of Canadian products early on Saturday and Canada immediately said it would retaliate, after last-ditch negotiations failed to resolve the latest strain in already tense relations between the...S2

• The United States imposed 50% tariffs on $20 billion worth of Canadian products early Saturday, and Canada immediately said it would retaliate, after last-ditch negotiations failed.S3

• Canadian Prime Minister vows retaliatory tariffs "dollar for dollar" following failure to secure a US trade agreement.S4

• US Trade Representative Jamieson Greer said Canada was "continuing its retaliation against the US," minutes before fresh Trump tariffs were due to come into effect. Canada says the terms proposed were "unfair."S5