Canada's foreign minister has warned the Trump administration that it will retaliate if the US applies new trade tariffs.
Foreign affairs minister Chrystia Freeland said her government strongly opposed any new possible tariffs, which would be mutally harmful, and warned that Canada would respond.
More than 75% of Canada's exports go to the US and 35 states count Canada as their leading export market.
President Trump has talked about renegotiating the North American Free Trade Agreement.
Ms Freeland spoke during a trip to Washington in which she met US secretary of state Rex Tillerson, House of Representatives speaker Paul Ryan and senators John McCain and Bob Corker.
Canadian prime minister Justin Trudeau is expected to visit Mr Trump this month.