Fifteen bodies, all but one of them decapitated, were found early today in the Pacific resort city of Acapulco, local media reported.
The victims, all men aged between 15 and 25, were discovered at dawn near a shopping mall along with several, threatening hand-written messages that are typically left as a calling card by drug cartels.
Local media said the notes were signed by Joaquin "El Chapo" Guzman, the leader of the Sinaloa cartel and Mexico's most wanted drug baron.
The tourist destination of Acapulco has been plagued in recent years with drug violence as the country's cartels fight for drug transport routes.
A burned-out truck and four other destroyed vehicles were found near the bodies. Four other murder victims were found in other parts of the city in separate incidents, local media reported.
The mayor of Zaragoza in Coahuila state was found dead with gunshot wounds yesterday.
More than 30,000 people have been killed in Mexico since late 2006 when President Felipe Calderon mobilised the army and other security services to confront drug traffickers who supply the United States.
The bodies are the largest single group of decapitation victims since 2006.
In 2008, a group of 12 decapitated bodies were found outside the Yucatan state capital of Merida. The same year, nine decapitated men were found in the Guerrero state capital of Chilpancingo.
Agencies