MEXICO CITY (AP) — Authorities in the southern Mexico state of Guerrero are investigating an apparent car bombing that caused no injuries, but damaged seven vehicles in a rural town.

Guerrero state security spokesman Roberto Alvarez said in a statement Wednesday that investigators determined a gas cylinder had been rigged inside the vehicle that exploded in the town of Xaltianguis, about an hour’s drive north of Acapulco.

Local media said the explosion occurred near offices of a local community defense force.

Violence has occurred sporadically between competing vigilante-like local police forces that have armed themselves against drug cartels.