Canadian Prime Minister Mark Carney announced retaliatory trade measures against the United States on Thursday, responding to President Donald Trump's latest tariff escalation on Canadian goods. Carney made the announcement in Ottawa after a phone call with Trump earlier in the week failed to ease tensions.

The measures follow Monday's announcement by the Trump administration of new levies targeting Canadian exports, which Carney's government described as unjustified and damaging to both economies. The prime minister said Canada would respond proportionately to the harm inflicted on Canadian workers and industries.

Carney said his government had consulted with provincial premiers and business leaders before finalising the countermeasures. Officials at Global Affairs Canada indicated the response would target specific American sectors in consumer and industrial goods while limiting harm to Canadian consumers.

The escalation marks the sharpest deterioration in cross-border relations since Carney took office, straining a trading relationship worth hundreds of billions of dollars annually. Business groups including the Canadian Chamber of Commerce warned that a prolonged dispute would raise costs and disrupt integrated supply chains, particularly in the automotive and agricultural sectors.

Carney urged Washington to return to negotiations, saying Canada remained open to dialogue but would defend its economic interests. He said the country would not be intimidated into accepting terms that harmed its workers.

"We will always stand up for Canada, for Canadian workers, and for Canadian businesses," Carney told reporters in Ottawa.