Gunmen attacked a town hall and murdered at least 20 people, including a mayor, in a southern Mexican state riven by turf wars between rival drug cartels, authorities said Thursday.
Soldiers guarded the bullet-riddled building in San Miguel Totolapan following Wednesday's massacre, in which Mayor Conrado Mendoza and his father, who held the job before him, were killed in broad daylight.
The mayor was in a work meeting when he was shot dead, municipal official Freddy Vazquez told reporters.
"At first we couldn't believe it. Our municipality is peaceful. We thought they were fireworks... but little by little we listened more closely and realized that they were gunshots," he said.
Police officers and city council workers were reported to be among the victims.
The attack came amid disputes between criminal groups operating in Guerrero state, including one known as Los Tequileros and another called La Familia Michoacana, Deputy Security Minister Ricardo Mejia said.
Located in the violence-wracked Tierra Caliente region, San Miguel Totolapan sits along a drug trafficking route disputed by different cartels.
"It's possible that the murders were due to a dispute between Los Tequileros and La Familia Michoacana for control of the municipality," security analyst David Saucedo told AFP.
Los Tequileros were previously active in San Miguel Totolapan for several years, mainly staging kidnappings for ransom.
But the group's influence dwindled after the death of one of its leaders in 2018 in a gunfight with police.
Just days before Wednesday's attack, alleged members of Los Tequileros had made threats to return to the town, local press reported.
- 'Cowardly murder' -
Guerrero, one of Mexico's poorest states, has endured years of violence linked to turf wars between drug cartels fighting for control of marijuana and opium production and drug trafficking.
"These are organizations that have been around for a long time. They did not emerge during this government, and we are trying to address the causes," President Andres Manuel Lopez Obrador told reporters.
Guerrero state attorney general Sandra Luz Valdovinos said that nobody had yet been arrested for the attack.
"There isn't yet enough evidence to determine who's likely responsible," she told local television.
Criminal gangs have cultivated close links to regional politicians, complicating efforts to pacify Guerrero despite the deployment of federal forces.
"Drug traffickers control various areas of the state and, instead of fighting them, the political parties have relied on them to win elections," Saucedo said.
More than 340,000 people have been killed across Mexico in a spiral of bloodshed since the government deployed the army to fight drug cartels in 2006.
Local-level politicians frequently fall victim to violence connected to corruption and the multibillion-dollar narcotics trade.
Mendoza is one of 94 mayors who have been murdered in Mexico since 2000, according to data from consulting firm Etellekt.
His party, the left-wing opposition PRD, condemned the "cowardly murder."
"We demand justice, enough of impunity," it wrote on Twitter.
Guerrero Governor Evelyn Salgado, of the ruling Morena party, said she had ordered a swift investigation into the massacre.
"There will be no impunity for the vicious aggression," she tweeted.