Four men hacked a Mexican politician to death with machetes and wounded a journalist who was apparently talking to him on the side of a road.

State assemblyman Osbaldo Esquivel Lucatero had stopped with his brother to meet the journalist on the outskirts of Morelia, the capital of Michoacan state. While the two were talking, four men pulled up in a car and attacked the two.

Mr Lucatero's brother drove the men to a hospital, where Mr Lucatero died. The journalist suffered serious injuries.

Acting state prosecutor Marco Vinicio Aguilera said robbery might have been a motive.

Mr Aguilera would not release the name of the journalist or the news outlet he worked for, citing the need for security.

Both journalists and local officials have been the targets of killings in recent years in Michoacan, where drug violence is so bad that some communities have formed self-defence groups.

Mr Lucatero was the former mayor of Buenavista Tomatlan, a town in one of the state's most violent areas.

He had been arrested in a 2009 sweep along with more than 30 state and local officials who were accused by federal prosecutors of protecting the La Familia drug cartel. The charges were later dismissed.