Four mayors have been shot dead by suspected drug cartel members since mid-August [Reuters]

Suspected drug gang members have shot and critically wounded the mayor-elect of a small town in Mexico's northern state of Chihuahua.

Ricardo Solis, who was recently elected as mayor of Gran Morelos, was shot in the head several times on Friday, less than 24 hours after armed men had killed the mayor of another town outside the city of Monterrey in Nuevo Leon state.

Mexican drug cartels have increasingly targeted such officials as they fight the government and each other, seeking control of drug markets and routes to the United States.

The traffickers use isolated, lightly patrolled towns to hide and to stash kidnap victims, weapons and drugs. They must co-opt or eliminate authority figures like mayors to assert control over both residents and police.

Little protection

Al Jazeera's Mariana Sanchez, reporting from Mexico City, said that local officials receive very little protection.

"The drug traffickers identify that very clearly. They know mayors are in charge of the local police and local roads which are key to their drug trafficking operations," she said.

Thursday's killing, which took place as Prisciliano Rodriguez Salinas and a personal aide drove home in the town of Doctor Gonzalez, was the fourth assassination of a public official since mid-August.

States close to the border with the US have seen an uptick in violence amid a dispute between the Gulf Cartel and Los Zetas, two formerly allied drug gangs.

The killings come despite the ongoing efforts of government forces to quell the violence that has left at least 28,000 people dead since Felipe Calderon, the president, launched a major offensive against the cartels in 2006.

Calderon condemned Thursday's slaying in Nuevo Leon in a message posted on the Twitter microblogging website on Friday.

"I reiterate my condolences for the cowardly assassination of Prisciliano Rodriguez, mayor of Gonzalez. We must redouble our fight against these criminals," he said. 

Source: Al Jazeera and agencies