Judges at the International Criminal Court have approved a formal investigation into possible crimes against humanity allegedly committed under the leadership of Philippine President Rodrigo Duterte in the context of his "war on drugs".
The ICC said in a statement that judges had approved a request by prosecutors to begin the investigation into potential murder as a crime against humanity.
Judges' assessment of material presented by prosecutors, was that "the so-called 'war on drugs' campaign cannot be seen as a legitimate law enforcement operation", but rather amounted to a systematic attack on civilians.
Human rights groups accuse Duterte of inciting deadly violence and say police have murdered unarmed drug suspects on a massive scale as part of the campaign.
Police deny this, and Duterte says the police are under orders to kill only in self-defence.
Philippines rights group Karapatan said the court's comments "reaffirms the views of victims and their families."
"Duterte and his cohorts should be made accountable for these crimes," it said after the ICC decision.
In a July speech, Duterte lashed out at the court, saying he would continue his fight against drugs.
"I have never denied (it), and the ICC can record it: Those who destroy my country - I will kill you," he said.
Although the Philippines has withdrawn from membership of the ICC, it was a member between July 2016 and March 2019, the period covered by the prospective investigation.
The judges said that relevant crimes appeared to have continued after that date, but that the court was limited to investigating those suspected to have occurred while the Philippines was a member.