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

Alejandro Arcos was found dead on Sunday in Chilpancingo, a city of around 280,000 people in the southwestern state of Guerrero. He had been mayor for six days.

Evelyn Salgado, the state governor, said the city was in mourning over a murder that “fills us with indignation”. His death came three days after the city government’s new secretary, Francisco Tapia, was shot dead.

Authorities have not released details of the investigation, or suspects. However, Guerrero is one of the worst-affected states for drug violence and drug cartels have murdered dozens of politicians across the country.