Tens of thousands of agricultural workers and their union representatives gathered at Mexico City's downtown plaza, the Zocalo, on Thursday to complain about the agriculture provisions in the North American Free Trade Agreement between Canada, the United States and Mexico.

Agricultural workers with tractors, cows and banners -estimated at over 100,000 by media reports - came together, urging the Mexican government to renegotiate the rules in the agricultural part of the Agreement that do away with customs tariffs for corn, beans, sugar and milk starting in 2008.

We have lost our way as a nation. We have given up sovereignty over food and energy, said Cruz Lopez, the speaker of the National Agricultural workers Confederation (CNC for its acronym in Spanish) according to Spain daily ABC.

Different organizations representing land workers said rules in NAFTA will diminish competition in Mexico, mainly affecting farmers. They also asserted that the U.S. has better agricultural financial assistance than Mexico.

The government in Mexico published a press release indicating an openness to talks with the agricultural organizations. However, Javier Lozano, the Job Secretary in Mexico discarded the possibility of renegotiating the agricultural section in NAFTA because it will result in different damages to the country.

Even though Mexico would be willing to do it (renegotiate), it couldn't make it in a one-sided way; I also think we would have other damages because if we open the agreement they might want to review other chapters from which Mexico benefits, he expressed according to La Jornada.

The free trade agreement among the North American nations began on January 1, 1994. In 2008 the last customs fee protections were eliminated causing great discontentment among land workers. Governmental officials have recognized that the agreement has helped commerce and the economy in Mexico but hasn't helped the agricultural sector which suffers from low salaries and insufficient agricultural financial assistance.

Farmers' leaders said they are planning to proceed with a national work stoppage which will include blocking roads, ports, airports and custom offices, according to La Jornada.