WASHINGTON — U.S., Canadian and Mexican negotiators are pledging to work quickly to update the North American Free Trade Agreement, a 23-year-old pact that President Donald Trump has called the worst trade deal in history.

The first round of NAFTA renegotiations were wrapped up Sunday. The three countries said they planned to meet again in Mexico from Sept. 1 to 5, in Canada late next month, and back in the United States in October.

They did not offer details on the five days of talks just completed.

U.S. Trade Rep. Robert Lighthizer declared Wednesday that the United States “is not interested in a mere tweaking” of NAFTA and will seek an ambitious rewrite of a deal the Trump administration blames for hundreds of thousands of lost U.S. factory jobs. NAFTA did away with most barriers, including tariffs, on trade between the U.S., Canada and Mexico.

NAFTA critics say the agreement encouraged manufacturers to move to Mexico to take advantage of lower-wage labor.

The Canadian and Mexican negotiators agree that NAFTA needs to be updated, but they have defended it as an economic success story for expanding trade between the three countries.

Mexican Economy Minister Ildefonso Guajardo said at the start of the Washington talks that he hoped differences could be narrowed in the next round of negotiations.