Ontario, Canada's most populous province, has enacted a 25% tariff on electricity that it exports to the U.S. in response to President Donald Trump's tariffs on Canadian goods.

Electricity from Ontario powers some 1.5 million homes and businesses in Minnesota, New York and Michigan.

Speaking at a news conference Monday, Ontario Premier Doug Ford said the widely expected new tariffs were a specific response to President Trump's tariff decisions.

"Believe me when I say I do not want to do this. I feel terrible for the American people who didn't start this trade war. It’s one person who is responsible, it’s President Trump," he said.

But Ford warned that Ontario would maintain and even intensify its tariffs if President Trump did anything to deepen the abrupt trade war.

“I will not hesitate to increase this charge. If the United States escalates, I will not hesitate to shut the electricity off completely," he said.

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President Trump plunged the U.S. into a trade war with North American allies Canada and Mexico when he used an economic emergency declaration to enact 25% tariffs on nearly all goods from Canada and Mexico, and 10% tariffs on energy-related imports from Canada, including oil, natural gas and electricity. In a separate order, President Trump also increased the tariff on all goods imported from China to 20%.

All three countries quickly announced they would take retaliatory action against the tariffs. The volatility has sent stocks plunging, eliminating all gains made in the S&P 500 benchmark index since President Trump took office in January. Trade experts and retail CEOs have warned that U.S. consumers will now pay higher prices, potentially in a matter of days.

"There'll be a little disturbance, but we'll be okay with that," President Trump told Congress last week.