(CNN) The mayor of a town on the popular holiday destination of Cebu was killed Wednesday, two months after two other town mayors were shot in other parts of the Philippines.
Ronda Mayor Mariano Blanco was shot by unidentified gunman in his office building in the early hours of Wednesday morning, according to CNN Philippines.
Provincial police said the investigation is ongoing and they have yet to identify any possible suspects or motive.
Blanco's death comes five months after the town's vice-mayor, Jonah John Ungab, was also killed by unidentified gunmen and two months after the mayors of Tanauan and General Tinio were shot dead. Police said it is unclear if any of the incidents are linked.
Tanauan City Mayor Antonio Halili was shot by a sniper in July during a flag-raising ceremony outside of the City Hall. The killing was captured on a video that showed scenes of panic seconds after the shot was fired.
In the video, Halili is seen standing in a line with government employees as the flag is raised and those in attendance sing the national anthem.
As the camera strays to film another group, a single shot rings out, followed by screams and a woman's voice, saying "Oh my God" in English.
Days later, Mayor Ferdinand Bote of the town of General Tinio in Nueva Ecija province was gunned down by a motorcycle-riding suspect in nearby Cabanatuan City.
In total, more than 15 mayors and vice-mayors have been killed since President Rodrigo Duterte took office in mid-2016, according to CNN Philippines.
Some of those killed have been linked to the drugs trade or crackdowns upon it. Duterte's administration has conducted an intensive war on drugs and anti-corruption campaign which has seen thousands of extralegal killings and allegations of widespread human rights abuses.