The mayor of a Mexican city plagued by gang violence has been murdered less than a week after taking office.

Photos circulating online among locals showed what appeared to be Alejandro Arcos’s severed head on top of a Volkswagen pick-up truck and the rest of his body inside a car in the Villas del Roble neighbourhood, east of the city.

Arcos was sworn in as the mayor of Chilpancingo, Guerrero, last Monday, and his death was confirmed by authorities late on Sunday.

Local media reported that Arcos had been decapitated, but state prosecutors offered no details when confirming his death in a statement on Sunday.

His death provoked unease across Chilpancingo, a city which is no stranger to political violence, with residents choosing not to leave their homes after 9pm and schools suspending classes.