Gunmen have shot dead the mayor of a town in northern Mexico, the fourth to be killed in a month

Prisciliano Rodriguez was the mayor of Doctor Gonzalez, a town 30 miles east of Monterrey. Monterrey was once considered one of the safest and richest places in Mexico but it has seen an upsurge in violence recently, blamed on gang warfare between drug cartels. In August 2010, the mayor of nearby Santiago was also killed. Edelmiro Cavazos was abducted from his house by armed men. His body, showing signs of torture, was found three days later. The killings are raising concerns about the security of public officials. The cartels appear to be targeting the mayors of small and medium-sized towns in the areas of Mexico most ravaged by drug-related violence. The Mexican Senate has asked the federal government to help mayors step up their personal security.