Negotiators from the United States, Mexico and Canada are still working to reach a deal on a new North American Free Trade Agreement (NAFTA), but arriving at a deal won’t be easy, negotiators told Reuters.

Negotiators said on Friday they will take a break until May 7, allowing time for consultations with the auto industry in Mexico and for U.S. Trade Representative Robert Lighthizer to visit China.

Now underway for eight months, the talks to renegotiate the agreement underpinning $1.2 trillion in trade entered a more intensive phase after...