Mexican authorities found at least 49 decapitated and dismembered bodies along a highway in a northern border state Sunday morning, officials said.
The remains were left along the road in Nuevo Leon state, between the cities of Monterrey and Reynosa.
A message written on a wall nearby appeared to refer to the Zetas drug cartel.
"This continues to be violence between criminal groups. This is not an attack against the civilian population," said Jorge Domene, Nuevo Leon's state security spokesman.