Federal Public Safety Secretary Omar Garcia Harfuch said four mayors requested protection on Monday, a day after Arcos' remains were found. The requests came from Guerrero and another violence-plagued state, Guanajuato. The situation in Guanajuato is so bad that ahead of the country's June elections, at least four mayoral candidates were killed.

Officials say four mayors in Mexico have asked federal authorities for protection after a colleague was beheaded last week in the southern state of Guerrero.

The gruesome killing represents yet another challenge for the country’s new president, who faces increasing pressure to show progress in the fight against violent cartels.