NAFTA talks are switching gears and slowing down as keyobstacles emerge, with Canada and Mexico rejecting what they see ashard-line U.S. proposals and negotiators exchanging their strongestpublic barbs yet.

U.S. Trade Representative Robert Lighthizer, Mexican EconomyMinister Ildefonso Guajardo and Canadian Foreign Minister ChrystiaFreeland wrapped up the fourth round of North American Free TradeAgreement talks in Washington Tuesday and said negotiations willrun through the end of March 2018, abandoning a December target.They also extended the time between negotiating rounds, givingthemselves more space to consider proposals.

The ministers cast the longer timelines as a positive way to diginto tougher disputes, pledging to continue to work out a dealwhile acknowledging that strong differences remain. They next meetin Mexico Nov. 17-21.