Agents for the Federal Police and Mexican Army watch over the crime scene where decapitated and dismembered bodies were found near a highway of Cadereyta, in the state of Nuevo Leon, Mexico, May 13, 2012. (Photo Source: Xinhua/Str)

At least 49 mutilated human bodies on Sunday were found next to a highway in the municipality of Cadereyta in the northern Mexican state of Nuevo Leon, Mexican authorities announced.

The number of mutilated bodies, found on a road adjacent to Monterey, amounts to 49, of which 43 of them are men and six are women, an official source said. Initially the authorities had counted 37 bodies dumped in black plastic bags beside the road in the morning.

The state prosecutor in Nuevo Leon, Adrian de la Garza, told a press conference that authorities received a report at around 4 a.m. (0900 GMT) on the presence of bodies, which were thrown from a truck at kilometer 47 of a highway that connects to the border city of Reynosa of Tamaulipas state, on the border with the United States.

He said that after the report, the highway was closed and the place was guarded by local police and soldiers and federal policemen. The experts from the state forensic service reached the site to perform the analysis of the remains and collect evidence.

De la Garza said that a message left near the scene may suggest that the extremely violent Zetas drug cartel was responsible, in which it confirmed the victims were from the Gulf Cartel and also launched threats against the Sinaloa Cartel and the state government.

The prosecutor said it will be harder to identify the victims, because all were decapitated and their hands were amputated.

"In all cases, to complicate the investigation, their heads and limbs had been cut off," he said.

The prosecutor said he had received no reports of missing people in recent days, "and less on that amount," so he did not rule out the possibility that "victims may be migrants" from other Latin American country.

Meanwhile, Jorge Domene, the government security spokesman of Nuevo Leon, said some bodies have tattoos of the Santa Muerte, a religious cult popular among members of organized crime.

The spokesman said the governor Rodrigo Medina had requested federal support for investigation to seek out those responsible for the slaughter.

This finding comes just four days after another 18 decapitated and mutilated bodies were found in two cars on a road near Guadalajara, Jalisco state capital, which was also attributed to the revenge of the drug cartels.

Mexico is experiencing an escalation of violence by the disputes between drug cartels and military deployment for combat, leaving more than 47,000 killed in drug-related violence for the last five years.

Nuevo Leon and especially its capital Monterrey, the wealthiest city in the country for years remained safe from the violence of drug cartels, whose clashes escalated from 2006, when President Felipe Calderon launched the "war against organized crimes."

Since 2010 the region has witnessed numerous bloody clashes between Los Zetas and the Gulf cartel. Los Zetas is now more powerful and engaged not only in drug trafficking but also in kidnapping and extortion, and have been identified as responsible for massive attacks against innocent civilians.

In August 2010, the Los Zetas cartel killed 72 Central American immigrants allegedly on the latter's refusal to join the criminal group.

In April 2011, 180 bodies were found in the town of San Fernando of Tamaulipas state, which was the worst slaughter on record since Calderon's anti-drug campaign and were also attributed to Los Zetas.

Most of the victims were Latin American immigrants heading to the U.S. border and were killed allegedly for refusing to join Los Zetas or did not pay the extortion they demanded.