MEXICO CITY - The political party that ruled Mexico for seven decades before voters threw it out a decade ago gained some momentum in state elections Sunday where the dominant issue was the country's skyrocketing drug violence.
Exit polls gave the opposition Institutional Revolutionary Party, or PRI, victory in at least nine of the 12 states where voting took place, a surprising loss in the southern state of Oaxaca and an uncertain outcome in two others.
Four of the states that voted are in the country's north and have been the scene of pitched battles between drug cartels and Mexican government authorities that have claimed thousands of lives.
"We are very content. ... Our victory is truly crushing in the states where there were elections," PRI leader Beatriz Paredes said.
The results gauged frustration that many Mexicans feel over the unchecked violence and whether that will influence the presidential vote in 2012, which could allow the PRI to regain power following its rout in 2000 after 71 years of its rule.
Some Mexicans fume over President Felipe Calderon's strategy of all-out war with drug gangs, saying it has failed to bring security. More than 23,000 people have died since Calderon, the leader of the National Action Party (PAN), came to office in late 2006.
Leaders of the PAN and the leftist Democratic Revolutionary Party (PRD), which formed an unlikely alliance in some states, trumpeted their apparent victory in Oaxaca.
"Our alliance ... has obtained full success, an unquestionable triumph," PRD leader Jesus Ortega said. "The next governor will be Gabino Cue."
Paredes, however, did not concede a PRI loss in Oaxaca, setting the state up for the kind of post-electoral violence that has occurred repeatedly there since the mid 1990s.
The polling unfolded in a tense landscape of escalating violence.
Presumed enforcers for drug gangs hung four bodies from overpasses before dawn in Chihuahua, the capital of the violence-wracked state of the same name that borders Texas and New Mexico. A local newspaper, El Heraldo, reported on its website that two of the victims may have been guards at a local prison.
In the capital of Tamaulipas, another border state, 30 bodyguards protected Egidio Torre Cantu as he cast a ballot. Torre's brother was the 2-to-1 favorite to win the governorship of Tamaulipas before gunmen ambushed his convoy June 28, the highest-level political assassination in more than a decade. The brother assumed the candidacy on behalf of a PRI-led coalition.