MONTREAL — The United States International Trade Commission on Friday struck down a Commerce Department recommendation that America place steep duties on imported Canadian jets, bringing an end to a trade dispute that has stoked tensions between normally close allies.

The case was brought by Boeing, which accused the Canadian jet maker Bombardier of subsidizing its products and selling them at unfairly low prices in the United States in violation of American trade rules. As is its usual practice, the commission did not explain the factors behind its decision.

The dispute — one of several trade conflicts to erupt between the two countries over lumber, newsprint and other goods — flared up amid wrangling over the Trump administration’s plan to drastically rework the 24-year-old North American Free Trade Agreement. The trade commission’s decision seemed likely to ease that strain.

The Commerce Department had decided that duties of nearly 300 percent should be placed on Bombardier’s new CSeries aircraft. But the trade commission, a quasi-judicial body of trade experts, disagreed.