Mexico's four presidential candidates signed a pact to respect the results of Sunday's elections and reject any acts of violence.

The signing of their commitment took place at the central office of the Federal Electoral Institute, or IFE, on the south side of the Mexican capital.

"The pact must be understood as a commitment of all political parties to respect in every electoral area the will of the citizens as expressed at the polls," IFE chair Leonardo Valdes said.

The document was signed by Josefina Vazquez Mota of the governing conservative National Action Party, Enrique Peña Nieto of the Institutional Revolutionary Party, leftist coalition leader Andres Manuel Lopez Obrador and Gabriel Quadri, candidate of the tiny Panal party.

The leaders of the respective parties were all present.

In his message, Valdes said that the signing "sends a clear message" against all types of violence that could break out as a result of these elections because the parties call on their followers "to resolve their differences in peace and by civilized means."

The documents says that "whatever" the result of the elections, the candidates express "their firm commitment to respect for legality."

They also promise to respect the rulings of the IFE and the high electoral court and to repudiate "any and all acts of violence."

In next Sunday's elections a total of some 2,127 public offices are up for grabs - a new president will be chosen, lawmakers in Congress will be replaced, and municipal and state authorities will be voted in.

Peña Nieto is widely favored to win the presidential contest.