Remains of a Mexican military Cougar EC725 helicopter in Villa Vieja community, Villa Purificacion, Jalisco State, on May 6, 2015
Mexico City (AFP) - One murdered candidate, others threatened, bodyguards assigned to gubernatorial wannabes and calls for a boycott: The June election campaign in Mexico's Wild West is off to a rough start.
The June 7 mid-term vote for federal and state seats will be the first major ballot test for President Enrique Pena Nieto, almost half-way through his six-year term.
But it will also be a challenge for the government's ability to ensure peaceful elections in the southwestern state of Guerrero and other violence-torn regions such as Jalisco, Michoacan and Tamaulipas.
Mexicans will vote for 500 federal deputies as well as governors in nine of 32 states and mayors in almost 900 municipalities.
Much of the focus has already been on Guerrero, a state that has drawn international attention since 43 college students were abducted by police and allegedly slaughtered by a drug gang last year.
While acts of violence could mar the election in Guerrero, experts say it is unlikely to have a major bearing on the outcome of the vote.
"There will be problems but it won't change the electoral process," said Raul Benitez Manaut, a security expert at the National Autonomous University of Mexico. "It's very hard to paralyze an election."
But the campaign has already been marked by threats and violence.
The mayoral candidate for Pena Nieto's centrist Institutional Revolutionary Party in the town of Chilapa was murdered last Friday when he was returning home from a campaign appearance.
Gunmen stopped the convoy of Ulises Fabian Quiroz, made him get out of his car and shot him at point-blank range.
In the same mountainous area, known for its gang turf battles, a candidate for Guerrero state governor, former Acapulco mayor Luis Walton, was confronted by armed men who pointed their guns at him despite a police escort.
The tense atmosphere prompted the PRI's substitute for Quiroz to refuse to run for mayor in Chilapa.
The leftist Democratic Revolutionary Party said one of its candidates in another Guerrero town was kidnapped on Tuesday, but the politician turned up later and said he had "only" been robbed.
Some political parties have urged their candidates to avoid campaigning at night.
In addition to the violence, parents of the 43 students and a radical teacher's union have called for an electoral boycott.
While the vote could be disrupted in small, remote villages, the boycott "will not succeed because the elections will surely take place in big cities of Guerrero," Benitez Manaut said.
- Gangs and vigilantes -
Guerrero is not the only state plagued by drug cartel violence ahead of the June elections.
The western state of Jalisco, home to the country's second biggest city Guadalajara, was hit by violence last week when the government launched an operation to dismantle the Jalisco New Generation drug cartel.
The New Generation gang downed an army helicopter with a rocket-propelled grenade, killing six soldiers. It had already killed 20 police officers in March and April.
Voters will also vote in the neighboring state of Michoacan, where farmers formed vigilante forces in 2013 to combat the Knights Templar drug cartel.
One of the federal congress candidates is Hipolito Mora, a founder of the vigilante movement, who was jailed over a deadly December shootout between his militia and a rival group but later released.
In the north, towns in the state of Tamaulipas have faced attacks from the Gulf cartel following the arrest of some of its leaders this year.