MEXICO CITY (Reuters) - The bodies of five women and four men were found piled up in front of a house in the Mexican city of Nuevo Laredo on the border with Texas, local authorities said on Thursday.

“The attorney general’s office of Tamaulipas is aware of the situation and has opened an investigation into the homicide of the nine people,” said a security official from the border state of Tamaulipas, who was not authorized to speak publicly.

Turf wars between the rival Gulf Cartel and Zetas gangs have racked the state for years, and in recent years some of Mexico’s worst drug violence has hit Tamaulipas.

Photos of the crime scene published on social media showed the bodies, some partly naked and covered by a thick sheet of paper, lying in front of the house.

Gang violence has worsened in the past few months and murders in Mexico are this year on track to reach their highest level since modern records began being kept in 1997.