Banners reportedly appear signed by country’s largest cartel denying responsibility for killings of 49 people.

Banners have appeared in northern Mexico apparently signed by the country’s Zetas drug cartel denying any role in the massacre of 49 people, whose mutilated bodies were found dumped in the neighbouring state of Nuevo Leon.

An employee of the prosecutors’ office in San Luis Potosi state said the banners were hung from overpasses in the city of Ciudad Valles, according to The Associated Press.

The employee was not authorised to speak on the record, and did not give the precise wording of the banners. The bodies were found on Sunday in the city of Monterrey with their heads, hands and feet hacked off.

A slogan scrawled on a stone arch nearby read “100% Zetas”, although it was unclear when the graffiti was daubed there.

Authorities have struggled to identify the corpses to gain clues into the latest in a series of massacres from an escalating war between rival drug cartels.

Forensic experts are yet to establish the identities of any of the corpses after the fourth massacre in a month.

None of the bodies examined so far showed signs of gunshots, Jorge Domene, Nuevo Leon state security spokesman, told local Milenio television on Tuesday.

Cartel rivalry

Mexico’s interior secretary, Alejandro Poire said on Monday that all those incidents resulted from the fight between the Zetas gang and the Sinaloa Cartel, which have emerged as the two main forces in Mexican drug-trafficking and other organised crime.

Mexico authorities have struggled to identify corpses

Zetas, formed by ex-military personnel in the 1990s, is present in nearly all of Mexico’s 32 states.

Some victims in earlier body dumps have turned out to be bakers, bricklayers and students; seemingly anybody who could be snatched off the streets in mass killings that one captured gang member said were designed to “cause terror”.

The 43 men and six women found on Sunday were dumped at the entrance to the town of San Juan in the municipality of Cadereyta about 175km southwest of McAllen, Texas.

There have been 74 killings in the first four months of this year in Cadereyta municipality, compared to 27 over the same period in 2011 and seven in 2010, according to figures from Nuevo Leon state prosecutors.

The massacre follows the discovery of 14 men left in a van in downtown Nuevo Laredo on April 17 and 23 people found hanged or decapitated in the same border city May on 4.

Eighteen dismembered bodied were left near Mexico’s second-largest city, Guadalajara, last week.

Drug violence has killed more than 47,500 people since President Felipe Calderon launched a stepped-up offensive when he took office in December 2006.