At least 11 people were killed and 12 injured in a shooting at a soccer field in the Mexican municipality of Salamanca on Monday. The incident occurred after a soccer game, where the local community and sports fans had gathered.

Beer cans, candles and blood-stained clothes were found in the field after the attack. Guanajuato state governor Livia Dennis Garcia said state and federal security forces had stepped up security and would bring the perpetrators to justice. Initial investigations suggest some of the dead were linked to local security companies, while messages from regional groups were found before the incident, which had disputed their rights to land.

Security experts say the attack was likely carried out by a local group to challenge a rival group, which may have been trying to provoke federal soldiers. Researchers say attacks in public places and during celebrations have a profound impact on social attitudes, making people afraid to go out in public. Last year, Guanajuato also witnessed attacks on public events, funerals and parties, which have limited community life and increased the power of criminal groups. The incident came just months before the start of a major international soccer tournament, which Mexico is jointly hosting with two other countries.