(Recasts, adds comments from Mexico foreign minister, background details)

Aug 30 (Reuters) - Foreign Minister Luis Videgaray said on Wednesday that Mexico will leave the negotiating table if U.S. President Donald Trump goes ahead with a threat to start the process of withdrawing from the North American Free Trade Agreement (NAFTA).

On Monday, Trump said he would probably need to terminate NAFTA to get what he considers a fair trade deal with economic partners Mexico and Canada, and revisited his campaign promise that Mexico would pay for a border wall.

Asked in Washington if Mexico would continue negotiating if Trump pulled the trigger on the six-month process of withdrawing from the trade deal, Videgaray responded with an emphatic "No."

Videgaray said he, U.S. Trade Representative Robert Lighthizer and U.S. Commerce Secretary Wilbur Ross agreed on Wednesday to continue with a "serious" renegotiation process. At around the same time, during a speech at a Missouri factory, Trump repeated his threat to shred the deal.

Videgaray and Economy Minister Ildefonso Guajardo traveled to Washington following Trump's near daily threats in the build up to the second round of NAFTA talks, due to be held in Mexico Sept. 1-5

A clause in NAFTA allows any of the three countries to withdraw from the deal after giving 180 days notice, and Trump has previously flirted with the idea of starting that process to ramp up pressure on the other trade partners.

Some experts in the United States argue that Trump would not be legally allowed to leave NAFTA without the approval of Congress.

The first five-day round of talks between the three countries concluded in Washington on Aug. 20, with all sides committing to follow an accelerated process in revamping the agreement.

(Reporting by Anthony Esposito in Mexico City; Editing by Frank Jack Daniel and Lisa Shumaker)