ACAPULCO, Mexico (AP) — The body of a murdered man was found Monday on the main highway to Acapulco, bringing to 31 the number of people killed in the Pacific resort city over four days.

The unidentified man was shot several times in the head and found under a pedestrian bridge with his shirt pulled over his face, said Fernando Monreal Leyva, director of the investigative police for Guerrero state, where Acapulco is located.

Leyva said federal, state and local police planned to meet Monday with the military to consider ways to beef up security in Acapulco, where 14 decapitated men and two police officers were among the unusually high body count since Friday evening.

Most of the killings occurred in just a few hours from Friday night to Saturday in non-tourist areas of the city.

But the officers were shot to death in front of tourists on Avenida Costero Miguel Aleman, the hotel-lined thoroughfare that runs along the bay.

Drug violence has increased in southern Guerrero state as factions of the Beltran Leyva cartel began fighting for territory after leader Arturo Beltran Leyva was killed by Mexican marines in December 2009.

Messages left with the 14 decapitated men said they were killed by “El Chapo’s People,” a reference to the Sinaloa cartel headed by Joaquin “El Chapo” Guzman.

Leyva would not say whether the notes indicated Sinaloa had joined the fight.

The decapitations were the largest single group found in Mexico in recent years.

In 2008, a group of 12 decapitated bodies were piled outside the Yucatan state capital of Merida.

The same year, nine headless men were discovered in Guerrero’s capital, Chilpancingo.

Among the other Acapulco victims, six people were shot and stuffed into a taxi, their hands and feet bound.

More than 30,000 people have died in drug violence nationwide since President Felipe Calderon launched a crackdown on cartels after taking office in December 2006 by deploying thousands of soldiers and federal police to drug hotspots.

Alejandro Poire, the government spokesman for security issues, said Monday that the increase in violence in Acapulco shows most of the killings in Mexico are a result of turf fights between drug gangs.

“They are vying for a place that, from the point of view of local drug sales, is extremely important,” Poire said.

Also Monday, the mayor of a town in central Mexico was shot to death as he drove with his wife and son, authorities said.

Abraham Ortiz Rosales, mayor of Temoac in Morelos state, was shot once in the head near the town of Jantetelco, said Morelos state Attorney General Pedro Benitez. Benitez said police had not determined a motive.

Ortiz Rosales had been threatened in June by men carrying assault rifles but the motive for that incident was never made public.

• SERGIO FLORES