"MEXICO CITY Dec 20, 2005 — The Mexican government, angered by a U.S. proposal to extend a wall along the border to keep out migrants, pledged Tuesday to block the plan and organize an international campaign against it. Facing a growing tide of anti-immigrant sentiment north of the border, the Mexican government has taken out ads urging Mexican workers to denounce rights violations in the United States. It also is hiring an American public relations firm to improve its image and counter growing U.S. concerns about immigration. Mexican President Vicente Fox denounced the U.S. measures, passed by the House of Representatives on Friday, as "shameful" and his foreign secretary, Luis Ernesto Derbez, echoed his complaints on Tuesday. "Mexico is not going to bear, it is not going to permit, and it will not allow a stupid thing like this wall," Derbez said. "What has to be done is to raise a storm of criticism, as is already happening, agains