Gunmen attacked a woman running for the Oaxaca state legislature on Saturday, wounding her while killing her husband and an assistant in the third shooting against politicians this week ahead of Mexican local elections.
Rosalia Palma, a member of the ruling Institutional Revolutionary Party (PRI), was traveling on a highway in a sport-utility vehicle when assailants fired 35 times with R-15 assault rifles and 9mm handguns, state police said.
Palma was seriously wounded while her husband, Efrain Cruz Bruno, and assistant, Talia Cruz Ibanez, died in the attack in the southern state. The candidate, running in a coalition with the Green Party, was taken to a hospital in the state capital.
The attack came two days after the leader of the leftist Democratic Revolution Party (PRD) in Oaxaca was found dead with three gunshot wounds to the head in the municipality of Tuxtepec.
Elsewhere, two politicians dropped out of the elections in the northwestern state of Sinaloa after another candidate was assassinated in the region plagued by drug violence.
Esteban Lopez Beltran and Saul Rubio were respectively running for mayor and local legislator in the municipality of Sinaloa as part of the July 7 elections taking place in 14 Mexican states.
They had been campaigning under the "Together You Win" coalition grouping the PRD, the fellow leftist Workers Party (PT) and the conservative National Action Party (PAN).
But Eleazar Armenta, campaign coordinator and city council candidate in the town of Sinaloa, was shot dead last Sunday.
"The outlook generated by the violence in this municipality is tough, which is why we decided to suspend campaign activities and warn the (PAN's) national and state leadership about the situation," local party official Yudit del Rincon told AFP.
The PRI has also toned down its campaigning in Sinaloa after Armenta's murder.
Mexico has endured a relentless wave of drug violence that left some 70,000 people dead between 2006-2012, when Felipe Calderon held the presidency. Dozens of local politicians were killed during that period.
Nearly 5,300 people have been killed in murders related to organized crime since President Enrique Pena Nieto took office in December, according to official figures.