The leading U.S. trade negotiator exchanged unusually sharp words with his Canadian and Mexican counterparts Tuesday, saying he was “disappointed” at their “reluctance to give up unfair advantages.”

In a press conference wrapping up a fourth round of negotiations to revise the North American Free Trade Agreement, a combative U.S. Trade Representative Robert Lighthizer said the Trump administration was determined to craft a better deal for U.S. companies and reduce a roughly $60 billion trade deficit with Mexico.

“Trade deficits do matter and we intend to reduce them,” Lighthizer said at a joint press conference with Canada’s Minister of Foreign Affairs Chrystia Freeland and Mexico’s Secretary of Economy Ildefonso Guajardo Villarreal.

However, Freeland cautioned earlier that an agreement “cannot be achieved with a winner take all mindset.” Guajardo said: “In order for the efforts of Mexico, the United States and Canada to be fruitful, we must understand that we all have limits.”

Despite the harsh words, the three ministers agreed to spread out the rounds of talks and extend them through the end of March, which Freeland called a sign of “goodwill.”

But there was little positive in the remarks beyond that.

Although NAFTA was designed to encourage investment and freer flow of goods among the three countries, Lighthizer said “continuing to design a national manufacturing policy largely dependent on exports to the United States for balance cannot long continue.”

And he said that “It is unreasonable to expect that the United States will continue to encourage . . . U.S. companies to invest in Mexico and Canada primarily for export to the United States.”

Freeland countered that U.S. proposals to increase U.S. national content in goods given favored treatment within NAFTA “would severely disrupt supply chains” and “put in jeopardy tens of thousands of jobs.”

Guajardo also appealed for reason. “Despite our current differences, we must ensure that the decisions we make today do not come back and haunt us tomorrow.”