President Donald Trump said Thursday he is renaming Lake Ontario to be known as “Lake America” in the United States as he escalates his trade war with Canada. The Republican president signed an executive order directing the Interior Department to update the lake's name in the US geographic naming service. Trump cannot force Canada to follow his preferred naming convention, however. Canadian Prime Minister Mark Carney pushed back against Trump's order, citing the name's Indigenous origins, as the row between the neighbors roiled on. "We know that America is changing. Their trading relationships, their foreign policies, their national monuments, their hydronyms," Carney said in a post on X. "Canadians also know that naming reality means calling it Lake Ontario – then, now and always." Trump has been floating the idea of the name change in recent days as the US announced it was imposing 50% tariffs on $20 billion worth of Canadian goods over the weekend after talks between the countries broke down. Trump has been needling America’s northern neighbor since he returned to the White House last year, suggesting the ally with whom the US once had warm relations should instead be absorbed as the 51st state. Canada responded to Trump’s import taxes this week by imposing retaliatory tariffs on $20 billion worth of American goods, including steel, dairy products, appliances and farm equipment. Trump, who signed the order as he was sitting at the Resolute Desk in the Oval Office, had a large sign behind him propped on a stand with a map of the Great Lakes. Over Lake Ontario, in big red letters, the map read “Lake America".