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.

Authorities confirmed Arcos’s murder after unverified social media images showed what appeared to be his remains.

Arcos’s social media posts show that he had spent his days in office supervising disaster relief efforts following Hurricane John last month, which caused severe flooding.

Pictures were posted to his Facebook account in the hours before his death of meetings with relief workers and residents.

Alejandro Moreno, a Mexican senator, said Arcos and Tapia were “young and honest officials who sought progress for their community”. He called on federal authorities to take charge of the investigation given Guerrero’s “ungovernability”.

Arcos’s Institutional Revolutionary Party called for justice. “Enough of violence and impunity! The people of Guerrero do not deserve to live in fear,” it said on Twitter/X.

Politicians, particularly at the local level, frequently fall victim to bloodshed connected to corruption and the multibillion-dollar drugs trade.

Guerrero is one of the worst affected states due to its location on the Pacific coast smuggling routes and Chilpancingo has long been the scene of turf battles between two drug gangs, the Ardillos and the Tlacos.

At least six candidates for public office were killed in the state in the run-up to Mexico’s 2 June elections.

More than 450,000 people have been murdered and tens of thousands have gone missing across Mexico since the government deployed the army to combat drug trafficking in 2006.