Gunmen in southern Mexico stormed a town hall and killed the mayor in a broad daylight attack that left at least 17 others dead on Wednesday, authorities said.

In a statement, the Guerrero state prosecutor’s office pledged to arrest those responsible for killing both the mayor of San Miguel Totolapan and his father, also a former mayor.

Local TV footage showed the facade of the municipal building riddled with bullets while people were heard screaming.

“Until now, we have 18 confirmed deaths and two injured”, - State Attorney General Sandra Luz Valdovinos told Milenio Television.

Along with Mayor Conrado Mendoza, police officers and city council workers were also killed, the prosecutor’s office told local media. The motive of the attack was not immediately known.