U.S.-Canada relations, already tense, are likely to deteriorate further after the United States went ahead early Tuesday with a decision to ban nearly $1 billion worth of Canadian imports, including alcoholic beverages, dairy products and motorcycles.

The ban amounts to barely a ripple in $880 billion worth of a two-way annual trade between the two northern neighbors. But it marks another ratcheting up of President Donald Trump's second-term trade war with America's longtime ally and trading partner.