Mexico City, Mexico (CNN) -- A town mayor was gunned down and killed in his office Wednesday afternoon in central Mexico, state and federal officials said.
Alexander Lopez Garcia was elected mayor of El Naranjo, in San Luis Potosi state, in 2009.
Witnesses told authorities that four armed and hooded men got out of a white truck in front of the city hall around 1:30 p.m., the official Notimex news agency reported. Two of the men waited out front while the other two went up to the mayor's office and shot him, the witnesses said.
No arrests have been made, officials said.
Lopez Garcia was the third mayor killed in Mexico in less than a month. A leading gubernatorial candidate also was killed in late June.
Drug cartels are suspected in the deaths of the politicians, a relatively recent development in the government's bloody war on organized crime that has seen more than 28,000 people killed in less than four years.