President Donald Trump has signed an executive order directing the U.S. federal government to rename Lake Ontario as “Lake America.”

Trump announced the change on Thursday, saying it would take effect immediately. The move follows comments he made earlier in the week on social media, where he said the United States was giving serious consideration to changing the lake’s name.

The executive order directs Interior Secretary Doug Burgum to update the Geographic Names Information System, which standardizes geographic names for use by the U.S. federal government. However, the order cannot require Canada, international bodies or private organizations to adopt the name “Lake America.”

A letter later shared by Trump said the U.S. Geological Survey had made the change and that it would begin appearing in printed documents over the following days.

The announcement comes amid ongoing trade tensions between the United States and Canada. Trump said the executive order was not intended to send a message to Canada but again criticized the country over trade and other issues.

Canadian Prime Minister Mark Carney rejected the name change, saying Lake Ontario should continue to be called by its original name. He noted that the name is more than 400 years old and comes from the Wendat word “Ontari’io,” meaning “the lake is beautiful, the lake is big.”

Carney said the name predates both Canadian Confederation and the United States Declaration of Independence, adding that “naming reality means calling it Lake Ontario.”

New York Governor Kathy Hochul, whose state is the only U.S. state bordering the lake, also said New York would not use the new name.

The renaming dispute comes as both countries impose new tariffs on each other’s goods. The United States has introduced tariffs on some Canadian imports, with additional tariffs on Canadian steel and automotive imports announced for January. Canada is expected to begin imposing matching tariffs of up to 50% on billions of dollars in U.S. goods from September 8.

Trump has previously pushed to rename other geographic locations, including changing the Gulf of Mexico to the “Gulf of America.” He also said on Thursday that he may consider changing the name of an ocean in the future.