The mayor of a town in one of Mexico's most violent drug corridors was shot to death, the second mayor killed in Mexico in two days.

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 Sunday that gunmen blocked a highway just over the state line in neighboring 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.

In recent years, business owners in Ciudad Altamirano say they have been forced to pay extortion to the Knights Templar drug cartel.

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.