MEXICO CITY, June 15 (Xinhua) -- The head negotiators for the North American Free Trade Agreement (NAFTA) will meet again in July, Mexico's Economy Minister Ildefonso Guajardo said on Friday.

Guajardo, who heads Mexico's negotiating team, said that in the meantime technical groups from NAFTA partner countries, including Canada and the United States, will continue to work on updating the trade deal.

"The ministerial meeting will surely take place in July," Guajardo told reporters on the sidelines of a gathering of Pacific Alliance envoys in Mexico City.

Mexico is "constructively committed to this negotiation," he added.

Guajardo and his counterparts -- Canadian Foreign Minister Chrystia Freeland and U.S. Trade Representative Robert Lighthizer -- originally planned to reach an "agreement in principle" by early May, but differences remain on rules of origin in the automobile sector and other issues.

In addition, steep U.S. tariffs on steel and aluminum imports went into effect on June 1, further complicating the negotiations to update the 1994 agreement.

The Pacific Alliance, a trade bloc founded in 2011 by members Mexico, Colombia, Peru and Chile to promote trade with Asia, has always been committed to integration and open markets, said Guajardo.

"But faced with the new winds that are blowing globally, we think it is essential to reaffirm our conviction to combat protectionism and ... promote the free flow of goods and services in the region, and with our new associate members," he said, referring to Australia, Canada, New Zealand and Singapore.

The alliance, which represents 38 percent of Latin America's GDP and 50 percent of the region's trade with the world, is to hold its 13th summit in the Mexican resort of Puerto Vallarta on July 23 and 24.