- At least 20 people - 16 men and three women - were killed in a shootout.
- Another person died en route to hospital.
- Earlier in March, the mayor of the Michoacan municipality of Aguililla, Cesar Valencia, was shot dead.
At least 20 people were killed in a Sunday night shootout in Michoacan, a western Mexican state plunged into violence by clashes between rival drug gangs.
An attack at a venue often used for hosting illegal betting on cockfights in the town of Las Tinajas was reported to the state attorney general at around 22:30.
The attorney general's office said the lifeless bodies of 16 men and three women were found at the scene, all bearing gunshot wounds.
It later said an additional person had died en route to hospital, while another five were being treated for injuries.
Michoacan's public security office said authorities were working to track down those responsible for the bloodshed.
Mexico has been trapped in a spiral of cartel-related violence since 2006, when the government launched a controversial anti-drug operation with federal troops.
The violence has since claimed more than 340 000 lives, most of them lost to organised crime, according to official figures.
Michoacan and neighboring Guanajuato are two of Mexico's most violent states due to turf wars between rival gangs involved in drug trafficking and other illegal activities, such as trade in stolen fuel.
Several powerful drug-trafficking gangs such as the Jalisco New Generation and Los Viagras cartels operate in Michoacan and battle each other for control of strategic territory.
Last month, an armed attack in the state was reported to have killed up to 17 people at a wake - in what authorities believe was a "revenge" raid by one cell of the Jalisco New Generation cartel against another.
The government was unable to confirm the death toll because no bodies were found, although DNA samples of 11 possible victims were collected at the site.
Earlier in March, the mayor of the Michoacan municipality of Aguililla, Cesar Valencia, was shot dead.
The violence in Michoacan also includes kidnappings and extortion targeting avocado producers.
The state is the world's biggest avocado-producing region and threats against a US inspector working there last month prompted the United States to suspend Mexican exports of the fruit for more than a week.
In 2021, Michoacan suffered 2 732 murders, a little more than eight percent of the 33 315 murders recorded across Mexico that year.
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