Updated

A mayor and two others were shot to death as they were traveling in a municipal vehicle on a highway in Mexico's Gulf coast state of Veracruz, authorities said Thursday.

Prosecutors said Maricela Vallejo, the mayor of the Mixtla de Altamirano municipality, was with her husband and her driver in the SUV when they came under fire from behind and both sides. Authorities found 31 bullet casings.

There was no immediate word on a possible motive.

The killing came a day after a mayor was slain in the southwestern state of Michoacan. Eduardo Otlica Avilés of Nahuatzen was kidnapped and his body found hours later.

Killings of politicians in Mexico rose last year during nationwide elections but then fell off.

Overall Mexico's homicides were up 9.7% in the first quarter of his year, compared with the same period in 2018.