U.S. and Mexican negotiators are working to reach a NAFTA cars deal this week that would allow Canada to rejoin talks and move toward resolving the toughest issues that affect all three nations, according to three people familiar with the discussions.

Getting an agreement on automobiles would let the U.S. turn its attention to demands that only affect Canada, such as increasing American access to the dairy market north of the border. It would also leave the thorniest issues that affect all three nations, like a so-called sunset clause and dispute-settlement panels, to be worked out with all countries at the table, according to the people, who asked not to be named discussing private talks.

The press offices of Mexico’s Economy Ministry and U.S. Trade Representative Robert Lighthizer declined to comment.

The U.S. has been looking for ways to discourage factories and jobs from moving to Mexico because its labor is cheaper. Canada’s automotive wages are closer to those of the U.S., making that issue one where its interests align with the U.S. Jerry Dias, the Canadian labor leader whose Unifor union represents autoworkers from his country, has long complained about wage and workers’ rights disparities that lead companies to move jobs to Mexico, a criticism that’s shared by U.S. President Donald Trump.

Mexican Economy Minister Ildefonso Guajardo, Foreign Minister Luis Videgaray and Jesus Seade, a representative of the next President Andres Manuel Lopez Obrador, are set to be in Washington on Wednesday afternoon to begin meetings with U.S. Trade Representative Robert Lighthizer that are expected to continue on Thursday. It will mark the third straight week of talks between the two nations, which are nearing an accord on content and salaries for auto manufacturing, the three unnamed sources said.

The U.S., Canada and Mexico are pushing for an agreement this month in order to allow sufficient time for Trump and Mexican President Enrique Pena Nieto to sign the pact before Lopez Obrador takes office Dec. 1. That would take the pressure off Lopez Obrador and allow him to focus on other priorities.

While Canada hasn’t attended meetings in the past three weeks, and Trump administration officials have been more publicly optimistic about talks with Mexico, Canada and Mexico have reiterated that they expect NAFTA to remain a three-nation agreement.

Canada’s Ambassador to the U.S., David MacNaughton, was set to be in Ottawa on Wednesday for meetings with officials from Prime Minister Justin Trudeau’s office in anticipation of rejoining NAFTA talks, according to a government official familiar with the schedule.