The foreign ministers of Mexico and Canada presented a unified front ahead of potential trade talks with Donald Trump’s administration, stressing the North American Free Trade Agreement has benefited all three countries.

Mexico’s Luis Videgaray and Canada’s Chrystia Freeland said Nafta should be re-negotiated with all three nations seated at the table, rather than in bilateral discussions.

“We very much recognize that Nafta is a three-country agreement,” Freeland said Tuesday at a panel discussion with Videgaray in Toronto ahead of private trade talks. “We really value our relationship with Mexico.”

Their talks come after Trump said trade with Canada only needed a “tweak” as opposed to a more thorough re-set with Mexico, a comment he made after Canadian Prime Minister Justin Trudeau’s visit to the White House last week. Mexican President Enrique Pena Nieto canceled a January meeting with the U.S. president after he tweeted that Nieto shouldn’t come unless Mexico was prepared to pay for a border wall to stop undocumented immigration.

Mexico’s relationship with the U.S. goes deeper than Trump’s “damaging” rhetoric, Videgaray said. He has been to meetings in Washington twice since the president’s inauguration and said he was confident the two nations’ issues could be resolved. “We will work it out in a way that is constructive and positive for both countries,” the foreign minister said.

‘Pandora’s Box’

Earlier Tuesday, Mexican Economy Minister Ildefonso Guajardo said he expected Nafta negotiations to start in the summer and that Mexico wouldn’t initiate talk about tariffs, calling any discussion of new import taxes a “Pandora’s box.”

“Nothing in the new Nafta should be a step backwards,” he said.

Freeland took a more reserved position, saying Trump’s trade team, including commerce secretary nominee Wilbur Ross, have yet to be confirmed. As a result, she said, Canada has had no specific discussions with the U.S. yet about Nafta. 

“We all collectively have to be quite careful not to get ahead of ourselves,” she said.

The morning event began with remarks by Brian Mulroney, a former Canadian prime minister who has been acting as an informal emissary to Trump for Trudeau. Mulroney, who signed Nafta in 1992 and who spoke to the president this weekend at Mar-a-Lago in Florida, was asked about reports that Canada would abandon its southern partner and deal directly with the U.S.

“You can forget this under-the-bus argument,” Mulroney said. “This under-the-bus stuff is for losers, not winners, and Canada is a winner.”

Canada’s ambassador to the U.S., David MacNaughton, said last month Canada will “cooperate on trilateral matters when it’s in our interest and we’ll be looking to do things that are in our interest bilaterally also.” The comments came at a meeting where Blackstone Group LP Chairman Stephen Schwarzman assured Trudeau’s cabinet that Trump was targeting Mexico, not Canada, in his trade overhaul.