Canada has filed a complaint with the World Trade Organization, accusing the US of breaking international trade rules.
The complaint targets US practices tied to tariffs imposed for alleged subsidies and below-cost product sales.
The action comes amid disputes between the two countries over issues such as dairy, aircraft sales and lumber.
The countries are also involved in tense efforts to renegotiate the Nafta trade deal.
President Donald Trump has threatened to scrap the agreement, which sets trade terms between the US, Mexico and Canada.
His administration has also taken a more protectionist stance on trade, taking action in a number of disputes it says concern the dumping of products in the US.
Canada filed the complaint with the WTO on 20 December. It was shared with the organisation’s members on Tuesday.
The complaint allows for 60 days of “consultation”. If it is not resolved in that time, it is subject to adjudication by a WTO panel.
