Police killed eight other suspects in the country's north including two in Manila during the past week as civil rights monitors warned the government against taking illegal shortcuts to fight crime.
Authorities have insisted the drug suspects were killed lawfully, with the officers firing back after being shot at during separate raids.
Four more drugs suspects were shot in the southern city of General Santos late Thursday after they fired at undercover police during a sting operation, regional police spokesman Superintendent Romeo Galgo said on Saturday.
He did not report any police casualties in what he described as a short firefight.
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Duterte, the long-time mayor of the southern city of Davao, won the May 9 presidential election in a landslide largely on a pledge to roll out his city's law-and-order policies nationally.
The controversial and acid-tongued politician captivated millions of Filipinos, and enraged his critics, with vows of ruthless tactics to end crime within six months.
The mayor warned security forces would kill tens of thousands of criminals and ignore human rights as he eradicated the scourge of drugs that many voters rated as their top concern.
Davao police reported Saturday that unknown gunmen shot and killed two suspected drug dealers this week.
One victim, attacked at an Internet shop on Wednesday, had been out on bail on a drug-related offence.
The second man was gunned down by two suspects outside a university campus on Friday.
Three petty thieves were also killed in a single attack by motorcycle-riding gunmen in another area of Davao also on Wednesday.