Canadian Foreign Minister Chrystia Freeland and Mexican officials on Tuesday called for the United States to lift steel and aluminum tariffs in order to create "true free trade" on the continent.
The US, Canada and Mexico signed a revamped North American free trade pact last October, but ratification has been delayed over the tariffs row.
Freeland's comments were the strongest yet linking the tariffs with the delay in ratifying the US-Mexico-Canada Agreement (USMCA).
"Now that we have a free trade agreement between our countries, now that that agreement is moving towards ratification in all three countries, now more than ever we feel is the time to have the tariffs lifted," Freeland told a press conference adding this would result in "true free trade."
Graciela Marquez Colin, Mexico's economy secretary, and Jesus Seade, undersecretary for North America, echoed her comments on their visit to Canada.
"I have optimism if we do things well, the Americans may come along," said Seade.
On Wednesday, Freeland will travel to Washington to press for a lifting of the tariffs in meetings with officials including US Trade Representative Robert Lighthizer and Senator Chuck Grassley.
Grassley said last month in a Wall Street Journal op-ed, "If these tariffs aren't lifted, USMCA is dead."
Earlier, Canadian Prime Minister Justin Trudeau in a telephone call with US Vice President Mike Pence also "stressed the importance of their removal" while exchanging views on USMCA ratification.
Last year, the US slapped tariffs of 25 percent on imports of steel products and 10 percent on aluminum.
Both Canada and Mexico are expected in the coming weeks to top up their respective retaliatory tariffs.