Canada will announce retaliatory tariffs against the United States on Tuesday after US President Donald Trump told Canadian leaders on Monday to “fall in line” or face consequences “far worse” than existing tariffs and Canada's Prime Minister Mark Carney accused Washington of trying to subordinate Canada. After trade negotiations crumbled at the eleventh hour, Trump's 50 percent tariffs on scores of Canadian imports kicked in over the weekend. The new levies, which took effect Saturday, are set to impact about 5 percent of Canada's annual exports to the US – or $20 billion in goods ranging from hockey sticks to agricultural products. Carney quickly promised that his government would roll out retaliatory measures “dollar for dollar” starting September 8. Additional threats have piled up in the meantime. Ontario Premier Doug Ford told The Associated Press on Monday that “everything is on the table," noting his province would be ready to cut off electricity and critical minerals to the US if the trade war worsens. Meanwhile, Trump suggested his administration could also increase taxes on Canadian automobiles next year. The US and Canada once held one of the world's most durable trade alliances, but the latest escalation plunges the North American neighbours deeper into a rupture that has kept both sides of the border on edge throughout Trump's second term in office. Steeper tariffs raise costs for businesses – and almost always trickle down to households in the form of higher prices.