A mayor who was running for a state assembly seat in southern Mexico has been killed by unidentified assailants, the latest in a recent spate of killings of candidates.

The leader of the governing Institutional Revolutionary Party "strongly condemned" the killing of Abel Montufar.

Montufar was on leave from his post as mayor of the city of Coyuca de Catalan in the southern state of Guerrero.

Guerrero Gov. Hector Astudillo wrote in his Twitter account Tuesday that Montufar "died in a cowardly and condemnable act."

Last week, a contender for the mayorship of the resort city of Zihuatanejo was killed in the same part of Guerrero state, and a town council candidate in northern Chihuahua state was among a group of people shot to death in an attack by gunmen.