Mexico City ? The public-relations and legal tactics Andres Manuel Lopez Obrador is using to contest his defeat in Mexico’s presidential election are aimed at annulling the results, leaders of Mexico’s ruling party charged Thursday.

As more people arrived in Mexico City ahead of a planned rally Sunday, National Action Party President Jose Espino and others called on panistas to be “moderate and measured” in responding to Lopez Obrador’s attacks.

The party’s Felipe Calderon, who beat Lopez Obrador, of the Party of the Democratic Revolution, by only about 240,000 votes, said a decision on whether to have a recount did not depend “on the will of the PAN, but on what the law says, and we will respect the decision of the Federal Electoral Tribunal.”

The tribunal, or Trife, is the nation’s highest electoral authority. Lopez Obrador is contesting results in 50,000 of the more than 130,000 polling places and has asked the panel to order a recount. The magistrates must issue a decision by Sept. 6.