In one killing, a man's body was left in the street and his head, wrapped in pink cardboard, on the sidewalk in front of a local newspaper. [REUTERS]
Thirteen people have been killed in two days in the northern Mexican border city of Tijuana, a surge in possible drug-related violence that comes just a week after President Felipe Calderon visited the town to praise what he called an improved security situation.
The latest incident occurred late on Tuesday night, when motorists found a decapitated body under a bridge on a road leading to the beach village of Playas de Tijuana.
The body appeared, like others found the day before, to have been hung from the bridge by its feet, using a rope.
The day before, two headless bodies were found hanging by their feet from a bridge in Tijuana. Graphic news photographs showed the men hanging upside down, being retrieved by security forces.
Last week, Calderon visited Tijuana to open Tijuana Innovadora, or Innovative Tijuana, a $5 million two-week conference aimed at improving the city's image and drawing investment.
But an apparent feud between groups of neighbourhood drug dealers has spoiled that attempt.
"We consider that there is a group trying to gain control of local drug sales," Fermín Gómez, Baja California’s deputy attorney general for organised crime, told the US San Diego Union-Tribune newspaper.
Authorities emphasised that the renewed violence was less than the situation two years ago, when heavily armed drug gangs roamed the city with near-impunity.
The Union-Tribune reported that a severed head wrapped in black plastic was also found on Tuesday around 1:30 pm by the side of a busy highway.
On Sunday night, gunmen opened fire on a barbecue, killing four men in their 20s, two of whome had criminal records, the Union-Tribune reported.
"These hangings from bridges, heads, shootouts ... it hadn't happened for a long time," Hector Elizaga, 40, who works at a Tijuana company that imports cars, told the Associated Press. "It seems like they are telling the president: 'What control? We are still in charge here'".
The AP also said that police reports showed 16 people had been killed since Sunday.
The murders broke a period of several months of relative quiet, and served as a reminder that Tijuana's death toll for the year could break the 2009 total.
The city just across the border from the southern California city of San Diego saw 664 murders last year. This year, so far, the total is 638.