At least 11 people were killed and 12 injured when armed men stormed a football pitch in Salamanca, central Mexico, on Sunday. Witnesses said the gunmen arrived in several vehicles and opened fire indiscriminately on locals at the Cabañas pitch in the Loma de Flores neighbourhood. Many families had stayed after a local football match to socialise. Among the dead were at least one woman and one child. Authorities have not yet confirmed the motive. Guanajuato, the state where Salamanca is located, reported the highest number of murders in Mexico last year. Neighbours heard around 100 shots during the attack. Local and federal security forces are investigating the deadly shooting. The attack occurred a day after other violent incidents in Salamanca where five men were killed and another abducted. Guanajuato has seen increased violence from gangs involved in oil theft, drug trafficking, and extortion. These gangs often attack tanker trucks carrying oil and tap pipelines of state-owned Pemex. Salamanca, home to a major Pemex refinery, faces frequent violent cartel attacks. Analysts blame rivalry between the Jalisco New Generation Cartel (CJNG) and the Cartel de Santa Rosa de Lima (CSRL) for brutal crimes in the region. Their illegal acts also affect the US through smuggling stolen fuel and drugs. The US State Department labelled CJNG a Foreign Terrorist Organisation last year and sanctioned CSRL more recently. US President Donald Trump has stressed fighting drug gangs trafficking heroin, fentanyl, methamphetamines, and cocaine. Trump previously claimed "cartels are running Mexico" and threatened land strikes against "narco-terrorists." The US has made at least 36 strikes against drug smuggling vessels at sea, killing about 125 people. Legal experts question the strikes' legality. Mexican President Claudia Sheinbaum recently handed over 37 major suspects to the US to boost joint counternarcotic efforts and avoid US unilateral strikes on Mexican soil.