Alejandro Arcos was killed less than a week after becoming mayor of Chilpancingo.
“His loss has left all of Guerrero society in mourning and fills us with indignation,” Guerrero state governor Evelyn Salgado wrote on X, adding that the public prosecutor’s office confirmed his death.
Salgado did not provide further details of the circumstances.
Arcos’s Institutional Revolutionary Party denounced the “cowardly crime” and called for justice.
“Enough of violence and impunity! The people of Guerrero do not deserve to live in fear,” it said on X.
Guerrero is one of the Mexican states most affected by drug cartel violence given its location along the Pacific coast.
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.
Politicians, particularly at the local level, frequently fall victim to bloodshed connected to corruption and the multibillion-dollar drug trade.