President Enrique Peña Nieto and the leaders of the main political parties signed the "Pact for Mexico" over the weekend at Chapultepec Castle in an effort to spur stalled political reforms.

The document was signed on Sunday by Institutional Revolutionary Party, or PRI, interim chairwoman Cristina Diaz, National Action Party, or PAN, chairman Gustavo Madero and Party of the Democratic Revolution, or PRD, chairman Jesus Zambrano.

"Mexico is starting a new stage in its democratic life. The time has come to meet and agree. The time has come to take the next step in perfecting democracy, moving toward an effective and efficient government," Peña Nieto, a member of the PRI who took office on Saturday, said.

The political leaders signed "an innovative agreement, which sets precise goals and concrete timetables for achieving them," the president said.

The pact is "realistic, detailing the instances and instruments for taking it from paper to reality," Peña Nieto said.

The PRD's Political Commission said later in the day Sunday that it did not recognize the pact signed by Zambrano with the other party leaders.

Peña Nieto has led a surprising comeback for the PRI, which governed Mexico from 1929 to 2000, lost the 2000 presidential election to the PAN and finished third in 2006.

During its 71-year reign - described by Peruvian Nobel literature laureate Mario Vargas Llosa as the "perfect dictatorship" - the PRI relied mainly on patronage and control of organized labor and the mass media, though it was not above resorting to outright vote-rigging and even violence. EFE