MANILA - President Rodrigo Duterte was swept to power in 2016 on a promise to get rid of narcotics in the Philippines, unleashing an unprecedented campaign against suspected drug users and dealers.
The authoritarian firebrand has defended the brutal crackdown — his signature policy — that rights groups estimate has killed tens of thousands of people.
More than five years after the bloody campaign began, the International Criminal Court on Wednesday authorized a full-blown investigation into the killings.
Here is a timeline of key events during the drug war:
2016: CRACKDOWN BEGINS
Duterte is sworn into office on June 30, 2016, promising a ruthless and deeply controversial war on crime.
Security services are given shoot-to-kill orders and even offered bounties for the bodies of drug dealers.
The former city mayor tells ordinary Filipinos to kill drug users.
"If you know of any addicts, go ahead and kill them yourself as getting their parents to do it would be too painful," Duterte says.
Since then, at least 6,181 people die in over 200,000 anti-narcotics operations, official data show.
ICC prosecutors in court papers estimate the figure to be between 12,000 to 30,000.
2017: 'CORRUPT' POLICE DEMOTED
Duterte orders police to take a step back from the drug war in January, describing them as "corrupt to the core" and instructing the Philippine Drug Enforcement Agency (PDEA) to lead after revelations that officers kidnapped and murdered a South Korean businessman.
It's not long before Duterte reinstates the force and re-launches the war under the name "Double Barrel Reloaded" -- so-called for the two-pronged police strategy to wipe out drugs.
He demotes the police again in October in the face of mounting public opposition to the drug war -- before ordering them back to the frontlines of the crackdown less than two months later.
2018: FIRST POLICE CONVICTIONS
Three policemen are sentenced to decades in prison for murdering a teenager during an anti-narcotics sweep, marking the first conviction of officers carrying out Duterte's drug war.
The 2017 killing of Kian delos Santos in a dank Manila alley sparks rare protests against the campaign.
Police say the 17-year-old was a drug courier who fired at them while resisting arrest. However, CCTV footage shows two of the policemen dragging the unarmed boy moments before he was shot dead.
2019: PHILIPPINES EXITS ICC
The Philippines officially exits the International Criminal Court in March, a year after telling the United Nations that it was quitting the world's only permanent war crimes tribunal.
The move comes after the ICC launches a preliminary examination in 2018 into Duterte's drug crackdown.
2020: UN REPORTS 'NEAR IMPUNITY'
The United Nations' human rights office says in June the drug war has unleashed widespread and systematic killing with "near impunity" for offenders.
Calling for an independent probe into human rights abuses, the office says police have been encouraged by the highest levels of government to use lethal force on drug suspects and thousands have been killed by officers and unknown gunmen since 2016.
But the UN Human Rights Council, which had requested the review of the crackdown, later passes a resolution for the UN to provide "technical assistance" to the Philippines to improve human rights in the country.
2021: ICC INVESTIGATES
The International Criminal Court approves a full-blown investigation into the drug war on September 15, after its judges say the crackdown could be a crime against humanity.
Duterte does not immediately respond, but his close advisers insist the tribunal has no jurisdiction in the Philippines and the president will not cooperate.
The announcement comes weeks after Duterte, who is barred under the constitution from seeking a second term, declares he will run for vice president in next year's elections.
Critics say the move is partly driven by fear of criminal charges, though there is debate over whether the vice president enjoys legal immunity.