Twenty-three people have been found murdered in the Mexican border city of Nuevo Laredo, including 14 whose dismembered remains were left in a van, authorities say.
Nine bodies were spotted about 1am hanging from an overpass at a major intersection, a source in the Tamaulipas state Attorney-General's Office said on Friday.
The five men and four women had their eyes covered and bore signs of torture, a municipal official said.
Accompanying the bodies was a message from the Los Zetas gang identifying the victims as employees of the rival Gulf drug cartel killed for "heating up the territory" by carrying out violent acts that attracted more attention from the security forces.
The message from the Zetas accused the victims of involvement in an April 24 grenade attack on municipal police headquarters in Nuevo Laredo, just across the border from Laredo, Texas.
Just hours later, the dismembered remains of 14 people were found wrapped in plastic bags inside a van abandoned in front of the Mexican customs service office in the city.
The victims' severed heads were left in coolers near Nuevo Laredo city hall.
The killers did not leave any message.
Los Zetas, a group founded by deserters from a US-trained special forces unit, started out as the armed wing of the Gulf cartel, but the two criminal organisations later had a falling out and the Zetas went into the drug business on their own account, gaining control of several lucrative territories.
Media reports say the Sinaloa and Gulf cartels have formed an alliance to fight Los Zetas, but this has not been confirmed by Mexican officials.
Fourteen dismembered bodies found on April 17 in a vehicle parked near city hall were accompanied by a message bearing the purported signature of Joaquin "El Chapo" Guzman, fugitive boss of the Sinaloa cartel.
The note said the Sinaloa outfit had come to Nuevo Laredo to cleanse the city of the Zetas.
Conflict among rival cartels and between criminals and the security forces has claimed more than 50,000 lives in Mexico since December 2006, when newly inaugurated President Felipe Calderon militarised the struggle against organised crime.
Photo: Mexican military in Nuevo Laredo on Independence Day 1999 (Getty Images)