Authorities in Mexico are investigating the slaying of nine men at a house in Monterrey, the largest city of the northeastern state of Nuevo Leon.

According to the state's attorney general, the men were watching a football match on television on Saturday when armed attackers burst into the house, herded women into the bathroom and then opened fire on the men. Seven men were killed on the spot and two others died of their wounds after being taken to local hospitals. The authorities also said small local drug-trafficking groups appeared to be involved, but not major drug cartels. Monterrey has been shaken by drug violence in recent years, due to the conflicts between two major cartels.