ACAPULCO, Mexico -- Both candidates for governor of the cartel-plagued state of Guerrero declared themselves winners Sunday evening as polls closed in an election shadowed by corruption scandals, political violence and the drug war.
The vote in Guerrero, home to the resort city of Acapulco and a battleground for feuding drug cartels, is the first of six gubernatorial elections this year in Mexico and sets the stage for the 2012 presidential election.
Two former party allies and second-cousins faced off in an acrimonious campaign. Even before election authorities began a preliminary count, each was confident of victory.
"All the trends favor us in an irreversible manner," said Angel Aguirre of the leftist Democratic Revolution Party, or PRD.
Manuel Anorve, of the Institutional Revolutionary Party, or PRI, made similar remarks at a separate news conference.
The PRI is hoping that a win in Guerrero would give it momentum as it seeks to regain the presidency, which it controlled for 71 years before losing it in 2000 to the National Action Party of current President Felipe Calderon.
The PRI lost Guerrero to the PRD in 2005.
The Guerrero race has demonstrated the far-reaching influence of the PRI, which ruled for decades as the single dominant party through paternalism and strong-arm election tactics that many Mexicans considered a quasi-dictatorship.
Even Aguirre comes from PRI roots; he recently split from that party to run on the PRD ticket.
During the bitterly contested race, his campaign accused PRI activists of badly beating one of his supporters, while the PRI claims two of its activists were the targets of political attacks.
The PRD demanded an investigation into Anorve's finances after the newspaper Reforma published allegations from a protected witness who said in court documents that the PRI candidate had received millions in cash from drug gangs.
Anorve angrily denied those allegations. The federal Attorney General's Office dismissed the significance of the documents, saying in a statement that secret witness testimony has no value unless backed by concrete evidence. The statement stressed that there is no criminal investigation against Anorve.
George Grayson, a Mexico expert at the College of William and Mary in Williamsburg, Virginia, predicted that if Aguirre wins, he would still back Mexico state Gov. Enrique Pena Nieto, a favorite for the PRI presidential nomination next year.
"In his race to succeed (President Felipe) Calderon, Pena Nieto faces a win-win situation in Guerrero," Grayson wrote in an analysis.
Meanwhile, the Guerrero election has been another demonstration of the PAN's failure to secure political dominance despite controlling the presidency since Vicente Fox's 2000 victory.
The government of Calderon, elected in 2006, is grappling with widespread frustration with Mexico's soaring drug-gang violence and an economy just starting to recovering from a severe recession.
Trailing in the polls, PAN candidate Marcos Parra dropped out of the Guerrero race at the last minute and threw his support behind Aguirre.
Such uncomfortable alliances between the conservative PAN and the leftist PRD helped defeat the PRI in three gubernatorial races last year.
Guerrero, a state of 3.3 million people, has been a hot spot of the bloodletting that has marred Calderon's presidency.
Earlier this month, the bodies of 15 men, all but one of them headless, were found on a street outside a shopping center in Acapulco, a coveted drug trafficking zone and the site of turf battles between the cartels.
There were 1,137 drug-related homicides in Guerrero in 2010, surpassing the 879 in 2009.