MANILA - Philippine authorities said Sunday they are investigating the brazen killing of a vice mayor near Manila, the third deadly attack by gunmen against local officials in less than a week.
The country has a violent, often deadly political culture, but watchdogs are concerned President Rodrigo Duterte's drug war may be emboldening assailants.
Police said there was no clear connection between the slaying Saturday of Alexander Lubigan, vice mayor of the city of Trece Martires south of Manila, and the killings of two mayors just days before.
However Wilnor Papa, Philippine spokesman for Amnesty International, told AFP that while political violence was not new, "Duterte he has aggravated it through his pronouncements."
"The Duterte administration is empowering vigilante killings," he added, citing Duterte's calls for ordinary citizens to kill drug dealers and his vow to protect officers who get sued while pursuing his drug campaign.
A sniper shot Mayor Antonio Halili, who was on Duterte's list of allegedly narcotics-linked officials, during a public ceremony at the city hall in nearby Tanauan on Monday.
A day later motorcycle-riding gunmen killed Duterte ally Ferdinand Bote, mayor of the northern town of General Tinio.
However, neither Bote nor Lubigan, the vice mayor killed Saturday, had known drug links. No clear motive has emerged yet.
"Election-related violence usually ramps up a few months before an election," Human Rights Watch researcher Carlos Conde told AFP, noting the next polls were 10 months away.
"The difference here really is the way Duterte has threatened officials with death and then they are being killed one after the other. That's hardly coincidence," Conde added.
According to a count by police, more than two dozen people were killed in "election-related violence" during campaigning for the May 2016 national elections.
At least 10 mayors including Halili and Bote have been killed since Duterte took office, while Lubigan, a member of a political party allied with the president, was the fifth vice mayor killed in that period.
Duterte ran on a law-and-order platform that included promises to kill thousands of people involved in the drug trade, including officials.
Authorities have acknowledged killing more than 4,200 drug suspects who resisted arrest, but rights groups say the actual number of dead is at least triple that and could amount to crimes against humanity.
Senator Francis Pangilinan, president of the opposition Liberal Party, on Sunday urged the government to do more to stop the killings.
"What we want is a safe, secure, and peaceful society, not a gangster land," Pangilinan said in a statement.
National police chief Oscar Albayalde told reporters Sunday the authorities were looking into possible motives for the killings, while noting it was a well-established fact that deadly attacks against elected officials spike "before, during and after the elections".
"There is nothing to fear because these (killings) are not systematic. It does not constitute a pattern," he added.