Philippine President Rodrigo Duterte on Friday defended his threat to kill criminals as "perfect" and vowed no let-up in his war on crime, as the death toll surged past 3,700.
International Criminal Court chief prosecutor Fatou Bensouda said on Thursday she was "deeply concerned" about the violence, and signalled Duterte could face prosecution by her body for his incitements to kill.
But Duterte launched a typically defiant counter-attack on Friday, defending his rhetoric and the crime war that is seeing more that 1,000 people killed every month.
"There is nothing wrong in threatening criminals to death. By that statement alone: 'You criminals, I will kill you. Do not fool around.' It is a perfect statement," Duterte said.
Describing his critics as "fools", Duterte reiterated his position he was not breaking any domestic laws by threatening to kill criminals and pledged the crime war would continue until there were no more illegal drugs in society.
"I will not stop. Be sure of it, you can cast it in whatever stone. I will not stop until the last pusher, until the last drug lord is taken away."
Duterte, 71, won May elections in a landslide on a pledge to eradicate drugs.
Last month Duterte said he would be "happy to slaughter" three million drug addicts, and likened his campaign to Nazi leader Adolf Hitler's efforts to exterminate Jews in Europe.
He later apologised for his Hitler reference, but said he was "emphatic" about wanting to kill all drug addicts.
Since Duterte took office, police have killed 1,578 people and 2,151 have died in unexplained circumstances, according to official figures released on Friday.
The total of 3,729 is 368 more than the previous police update released last week.
The United States, the European Union and the United Nations have condemned alleged extrajudicial killings and warned of a breakdown in the rule of law.
Bensouda indicated on Thursday that Duterte was at risk of joining the likes of late Libyan dictator Muammar Gaddafi and Sudan's President Omar al-Bashir, in being indicted by the International Criminal Court.
"Let me be clear: any person in the Philippines who incites or engages in acts of mass violence including by ordering, requesting, encouraging or contributing... to the commission of crimes within the jurisdiction of the ICC is potentially liable for prosecution before the Court," she said in a statement.
The Philippine government this week invited UN Special Rapporteur Agnes Callamard to investigate the killings.
But Duterte vowed on Thursday to "humiliate" her and any other critics if they dared to come to the Philippines and investigate.
Polls show Filipinos overwhelmingly support Duterte's war on crime.
President Rodrigo Duterte says he's not breaking any domestic laws by threatening to kill criminals.