MEXICO CITY, Jan 26, (AP): Cans, candles and blood-stained clothing littered a soccer field in central Mexico on Monday, a day after gunmen killed 11 people and injured 12 others during a gathering after an amateur match. While authorities investigate the killings, Guanajuato state Gov Libia Dennise García said Monday that "security in the region has been reinforced” with state and federal forces.

She said on social media that the state "will act decisively to protect families, restore peace to the community and bring those responsible to justice.” The massacre took place in the municipality of Salamanca, in the state with the highest number of homicides in the country. The region has been wracked by intense violence linked to the territorial dispute between the local Santa Rosa de Lima cartel - a violent group primarily dedicated to fuel theft and trafficking - and the Jalisco New Generation Cartel, CJNG.

According to a federal official familiar with the case who requested anonymity because it is an ongoing investigation, initial evidence suggests that some of the deceased people were linked to a private security company associated with the CJNG. The official added that prior to the attack, messages attributed to the Santa Rosa cartel were found mentioning their dispute with Jalisco.

The attack comes a few months before the start of the FIFA World Cup, which Mexico is co-hosting with Canada and the United States, and as the government of Mexican President Claudia Sheinbaum not only seeks to highlight its progress in security, but is also promoting local soccer and its fan base as the "powerful tool for integral development” of the population, according to Mexican Interior Secretary Rosa Icela Rodríguez.

Salamanca Mayor César Prieto - the only official to provide early details on Sunday - described the massacre as part of a "wave of violence” and appealed to Sheinbaum for help. Nancy Angélica Canjura, researcher for Causa Común - a nongovernmental organization that analyzes data on insecurity - said that regardless of whether or not those killed were linked to criminal activity, the fact that the attack occurred in a public place and during a festive activity has a large social impact because it stays in the public consciousness that "you can't go out by choice … you shouldn't stay in public spaces.”