Reporting from Mexico City — Nine workers from two prominent Mexican polling firms were missing Tuesday in the violence-plagued state of Michoacan, which holds elections this fall.
Six pollsters from the Consulta Mitofsky firm vanished over the weekend while surveying residents in Apatzingan, a town in a rural area that has seen bloody clashes between Mexican security forces and a violent drug-trafficking gang.
On Tuesday, a separate firm, Parametria, reported that three of its field workers disappeared while on the job in the same region.
Parametria's director, Francisco Abundis, said the workers were part of a 25-member team hired by the leftist Democratic Revolution Party to prepare a companion survey to the one being done by Mitofsky. Both firms were hired to gauge the relative popularity of the party's potential mayoral candidates in Apatzingan, an agricultural town of 123,000.
Abundis told a radio interviewer that colleagues noticed that three workers were missing Monday, just as news was emerging that the Mitofsky pollsters had disappeared.
On Saturday afternoon, three Mitofsky workers lost contact with the rest of their team in Apatzingan after checking in by phone. Three colleagues who went looking also disappeared, Mitofsky director Roy Campos said in a separate radio interview.
Michoacan authorities said "hundreds" of police were searching for the workers. Alejandro Poire, security spokesman for President Felipe Calderon, said the disappearances showed the need to speed up efforts to curb kidnapping and other crimes.
"We're feeling very desperate. It's been three days," said Elizabeth Ramirez, who said her sister, Claudia, 35, and her sister's common-law husband were among the missing Mitofsky pollsters.
The disappearances underscored the lawlessness prevailing across big swaths of Mexico as Calderon's government pursues a military-led offensive against drug gangs. Thousands of people have gone missing during the 4 1/2-year-old drug war.
Polling workers conducting face-to-face interviews in conflict zones confront special risks. Pollsters have been threatened and chased away in hot spots, including the northern border states of Tamaulipas and Chihuahua.
"There are areas of the country where you cannot enter, and if you do, you run the risk of being kidnapped," said Jorge Buendia, a Mexico City pollster and analyst.
During last year's gubernatorial vote in Tamaulipas, Abundis said, Parametria's pollsters were unable to conduct exit polls in four municipalities, including the port city of Tampico.
He said team members in Michoacan were told to skip zones they believed too dangerous. "We had been in this same municipality a month ago without a problem," Abundis said. "That's why it surprised us."
The disappearances came as polling firms mobilize for next year's presidential election. Michoacan voters will choose a new governor and 113 mayors in November. Calderon's sister, Maria Luisa, is running for governor as part of the president's conservative National Action Party.
Cecilia Sánchez of The Times' Mexico City bureau contributed to this report.