OTTAWA — First were the tariffs on Canadian softwood lumber. Then came a trade action over a Canadian jetliner, and duties on newsprint. Most recently the United States and Canada battled over potentially crippling duties on steel and aluminum that President Trump introduced last week.

And all along the two countries have been fighting over renegotiations of the North American Free Trade Agreement.

Now comes the latest slight to Canada from its closest ally and nearest neighbor: a report by The Washington Post on Thursday that Mr. Trump boasted at a private fund-raising event that he made up an assertion that the United States had a trade deficit with Canada during a meeting with Prime Minister Justin Trudeau.

Trade with the United States is a critical part of Canada’s export-dependent economy, and the actions and statements from the Trump administration concerning the two countries’ economic relationship have provoked equal parts anxiety, puzzlement and anger within Canada.