Senior trade officials from the U.S., Canada and Mexico will meet again in Washington in an intensified push to reach a NAFTA agreement in the next few weeks.

Talks will pick up on Tuesday, after Cabinet-level members vowed on Friday to keep up the momentum following consultations with their technical teams over the weekend.

Mexican Economy Minister Ildefonso Guajardo said last week that after seven months of discussions, the three sides have entered a concentrated phase where "my negotiating team is practically living in Washington." Still, major differences remain over key U.S. demands.

Mexico scored a separate commercial victory over the weekend with a deal in principle to update a 17-year-old free-trade agreement with the European Union. Guajardo jetted to Brussels to help close the deal.

Chrystia Freeland, Canada's minister for foreign affairs, said Friday that North American Free Trade Agreement negotiators have been making good progress on updated rules for cars, which she said will be at the heart of any eventual updated NAFTA.

"We have had some very energetic and productive conversations," Freeland told reporters on the steps of the U.S. Trade Representative's office following meetings with her counterparts. "We are certainly in a more intense period of negotiations, and we are making good progress."

President Donald Trump on Monday said again that he could make Mexican immigration curbs a condition of a new NAFTA deal, highlighting that a deal is still far from certain. Trump in a Twitter post said Mexico "must stop people from going through Mexico and into the U.S.," adding "We may make this a condition of the new NAFTA Agreement. Our Country cannot accept what is happening!"

Foreign Minister Luis Videgaray responded it's unacceptable to demand that Mexico tie changes to its "sovereign" immigration policy to an updated trade pact.

"Mexico decides its immigration policy in a sovereign manner, and the migration cooperation with the U.S. takes place in such a way that Mexico agrees," Videgaray said on Twitter.

Topics of this week's talks will include automotive rules, agriculture, and legal and institutional matters such as dispute settlement mechanisms.