MEXICO CITY, July 25 (Xinhua) -- Mexican President Enrique Pena Nieto on Wednesday called on the members of the North American Free Trade Agreement (NAFTA) to reach a deal soon.

The trade agreement, signed between Mexico, Canada and the United States in 1994, was opened to renegotiation in August, but several demands made by the United States have bogged down the talks.

"I am stressing the importance of continuing to work on a constructive and comprehensive renegotiation of NAFTA, with the goal of concluding (a new deal) in the short term," Pena Nieto said during a meeting with the Canadian delegation led by Foreign Minister and chief NAFTA negotiator Chrystia Freeland, according to a statement from the president's office.

At a press conference earlier Wednesday, Freeland and Mexican Economy Minister and chief negotiator Ildefonso Guajardo acknowledged the three sides have made much progress, but still face "challenges."

"Today, nearly 11 months since the talks began, we can be proud that practically two-thirds of the agreement's modernization is almost complete," Guajardo said.

"As always, there are challenges, challenges we are reviewing today as part of our NAFTA agenda to try to move the negotiation forward and land it on safe ground," Guajardo added.

The tripartite talks are set to resume in Washington on Thursday and negotiators will strive to reach consensus on pending issues such as financial market uncertainties before the U.S. midterm elections in November, said Guajardo.

However, that goal has proven elusive, mainly due to U.S. demands for substantial changes to existing rules of origin in the automotive industry, among others.

U.S. President Donald Trump, who insisted the deal be renegotiated in a bid to secure better terms for American industry, has said if the NAFTA partners fail to reach an agreement, his country will negotiate separate bilateral deals with Mexico and Canada.

Both Mexico and Canada have stressed the importance of preserving the trilateral treaty for "the good of the interests of our countries, for the good of North America."

Freeland also met with Mexico's President-elect Andres Manuel Lopez Obrador, who takes office on Dec. 1. His economic team is participating in the negotiations.