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 U.S. geographic naming service. Trump cannot force Canada to follow along, however.

Trump has been floating the idea of the name change in recent days as the U.S. 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 U.S. 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.

AP Washington correspondent Sagar Meghani reports President Trump has signed off on renaming Lake Ontario in the U.S.

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.”

On the other side of the president was another map with the words, “MAKING THE GREAT LAKES EVEN GREATER.”

Trump said as he was signing the order that he’d “notified all of the various people that we have to notify. So, we’ve done everything that you have to do.”

“And this is official, effective immediately,” he added. (AP, excluding headline)

•President Donald Trump holds the executive order Thursday renaming Lake Ontario as Lake America. (Evan Vucci/Reuters)