A councilman from the leftist Party of the Democratic Revolution, or PRD, was murdered in a city in central Mexico, while a mayoral candidate belonging to the Institutional Revolutionary Party, or PRI, was kidnapped and beaten in the southern state of Guerrero ahead of Sunday's general elections.

Luis Antonio Contreras, a member of the PRD, was murdered on Saturday, officials said.

Contreras served on the council in Valle de Santiago, a city of some 100,000 people in Guanajuato state.

Media reports differed on how Contreras was killed, with some outlets reporting that he was killed during an argument, while others said gunmen opened fire on him from a moving vehicle that did not have tags.

PRD officials blamed supporters of the rival National Action Party, or PAN, for the killing, but this information has not been confirmed and some reports said the murder may be linked to a personal matter.

Valle de Santiago is run by the PRD, but Guanajuato is governed by the PAN.

The PRI mayoral candidate in a city in Guerrero, meanwhile, was kidnapped on Saturday night, beaten and released a few hours later, police said.

Cesar Garibay Gutierrez, who is running for mayor of Marquelia, was found early Sunday by community police officers.

The mayoral candidate was spotted around 4:00 a.m. in the city of San Luis Acatlan, the Regional Community Authorities Coordinator said.

Garibay Gutierrez was found at a place about 30 kilometers (18 miles) from where he was abducted.

The mayoral candidate was kidnapped by unidentified individuals as he arrived at his house around 9:30 p.m., Javier Figueroa, who is running for a council seat in Marquelia under the PRI banner, said.

Garibay Gutierrez was driven to an unknown location, Figueroa said.

About 100 marines and some state police officers launched a search for the politician, who was found with his hands bound on the highway that links Marquelia, a city of some 11,000 people, with the city of Tlapa.

The cities are located in a mountainous area with a large Indian population in southern Mexico.

The PRI mayoral candidates in Apaxtla de Castrejon and Tixtla, two other cities in Guerrero, were also kidnapped and later released in recent days.

Nearly 80 million people are eligible to vote in Sunday's general elections, with the presidency, 628 congressional seats and thousands of other posts up for grabs. EFE