Canada has filed an expansive complaint with the World Trade Organization accusing the US of breaking international trade rules.

The complaint challenges the ways that the US investigates products for subsidies and below-cost sales.

The US called the claims “unfounded”.

The action comes amid disputes between the two countries over areas such as dairy, aircraft sales and lumber as well as efforts to renegotiate the North American Free Trade Agreement.

Eric Miller, president of the Rideau Potomac Strategy Group, which consults on North American trade issues, said the scope of the filing is “unprecedented”.

“It is global, it is over many years, it is systematic and so this is something that certainly, in the realm of WTO cases, is outside the norm in terms of its reach and its ambition,” he said.

Canada’s ministry of global affairs said the petition is part of broader litigation aimed at preserving forestry jobs.

In November, it filed a complaint with the WTO contesting US duties on Canadian softwood lumber producers.

“We continue to engage our American counterparts to encourage them to come to a durable negotiated agreement on softwood lumber,” Chrystia Freeland, Canada’s minister of foreign affairs, said.

Mr Miller said Canada may hope the filing will apply pressure on the US in its disputes, while allowing the country to make a broader statement about the importance of international organisations and rules.

He added that it is a sign that the negotiations over NAFTA are not going well.

President Trump has threatened to pull the US from the agreement, while Canada is trying to galvanise support for the existing deal.

A part of the agreement that creates a process for NAFTA partners to appeal tariff decisions is one of the thorniest issues in the talks.

Read the full article over at the BBC here.

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