Ambrosio Soto was mayor of a township that includes Ciudad Altamirano, a known haven for drug traffickers in southern Guerrero state.
Roberto Alvarez, spokesman for southern Guerrero state, said yesterday that gunmen blocked a highway just over the state line in neighbouring Michoacan state with pickup trucks and opened fire on the mayor's vehicle late Saturday. He said two federal officers serving as Soto's bodyguards were wounded in the attack.
Soto had received threats and was under protection from federal police. A local drug gang had reportedly threatened him because he refused to turn over part of the city budget as a protection payment.
The leftist Democratic Revolution Party said the mayor had taken "special protection measures after he dared to file complaints and complained that the security patrols had abandoned the area.
The party said 75 mayors have been killed in the last decade.
On Saturday, a mayor and four others were shot to death in the town of San Juan Chamula in southern Chiapas state.