Forty-nine decapitated and mutilated bodies were found Sunday along a highway connecting the industrial hub of Monterrey in northern Mexico to the U.S. border, in what may signal an escalating war of terror among drug gangs. 

Mexico's organized crime groups often abandon multiple bodies in public places as warnings to their rivals, though Nuevo Leon state Attorney General Adrian de la Garza said he did not rule out the possibility that the victims were U.S.-bound migrants.

The bodies of the 43 men and six women were found in the town of San Juan on the non-toll highway to the border city of Reynosa at about 4 a.m. (5 a.m. EDT; 0900 GMT), forcing police and troops to close off the highway. Nuevo Leon state security spokesman Jorge Domene said at a news conference that a banner left at the site bore a message with the Zetas drug cartel taking responsibility for the massacre.

Domene said the fact the bodies were found with the heads, hands and feet cut off will make identification difficult. The bodies were being taken to Monterrey for DNA tests.

De la Garza said the victims could have been killed as long as two days ago at another location, then transported to San Juan, a town in Cadereyta municipality, about 105 miles (175 kilometers) west-southwest of McAllen, Texas, or 75 miles (125 kilometers) southwest of the Roma, Texas, border crossing.

Mexican drug cartels have been waging an increasingly bloody war to control smuggling routes, the local drug market and extortion rackets, including shakedowns of migrants seeking to reach the United States.

A drug gang allied with the Sinaloa cartel left 35 bodies at a freeway overpass in the city of Veracruz in September, and police found 32 other bodies, apparently killed by the same gang, a few days after that. The goal apparently was to take over territory that had been dominated by the Zetas. Twenty-six bodies were found in November in Guadalajara, another territory being disputed by the Zetas and the Sinaloa group.

So far this month, 23 bodies were found dumped or hanging in the city of Nuevo Laredo and 18 were found along a highway south of Guadalajara, Mexico's second-largest city.

In April, police found the mutilated bodies of 14 men in a minivan abandoned in downtown Nuevo Laredo, along with a message from an undisclosed drug gang. Also in April, the tortured and bound bodies of seven men were dumped in the Pacific port city of Lazaro Cardenas along with messages signed by allies of the Sinaloa drug gang.

Officials last year found 183 bodies in mass graves in the Tamaulipas state town of San Fernando. They were believed to have been migrants killed by the Zetas drug cartel. Another 72 migrants, many of them from Central America, were found slain in San Fernando in 2010.

Based on reporting by the Associated Press.

Follow us on twitter.com/foxnewslatino
Like us at facebook.com/foxnewslatino