Washington, Oct. 27 -- President Donald Trump announced an additional 10% in tariffs on Canada in response to an advertisement by the province of Ontario that is critical of the levies, escalating tensions in one of the world's biggest bilateral trade relationships. Trump's Truth Social post follows days of public clashes over the ad, which invoked former President Ronald Reagan's stance as a free trader and triggered the current US president's ire, prompting him to suspend trade negotiations with Canada. "Because of their serious misrepresentation of the facts, and hostile act, I am increasing the Tariff on Canada by 10% over and above what they are paying now," Trump said Saturday. The US president didn't specify the scope of his new measure. While Canada faces a US base tariff of 35%, the rate doesn't apply to most Canadian goods because of an exemption for products and shipments made within the rules of the US-Mexico-Canada Agreement. That means millions of barrels of oil per day still flow from Canada to the US tariff-free, for example....