"It is apparent that the ICC is being utilised as a political tool against the Philippines," Duterte said, adding that the body had showed a "propensity for failing to give due respect" to the Philippines. He also accused United Nations officials of "baseless, unprecedented and outrageous attacks on my person."
For a country to withdraw from the court, it must formally notify the UN secretary-general of its decision. It will then be a year before this takes effect. Throughout that time, the country remains a full member of the court and the prosecution of any international crime that it is allegedly linked to can continue.
Duterte's angry words were a sharp departure from February, when he said he welcomed the court's inquiry as a chance to prove his innocence. "If they want to indict me and convict me, fine," he said at the time. "I will gladly do it for my country."
There was no immediate reaction from the court in The Hague.
The court said in February that its initial inquiry would seek to determine whether there was a basis to proceed with an investigation. Jude Sabio, a Filipino lawyer, filed a 77-page complaint with the court last April accusing the president and 11 other officials of mass murder and crimes against humanity.
The complaint accused Duterte of masterminding a campaign of extrajudicial killings dating from the 1980s, when he became the mayor of the southern city of Davao, and escalated after he became president.
"It is clear that Mr Duterte is nervous about the case and is exploiting technicalities to avoid an imminent probe," Sabio said on Wednesday. "Duterte is just digging his own grave at the ICC."
Various international and local rights groups have placed the death toll from the drug crackdown at around 12,000, including killings by unidentified gunmen as well as police officers. Duterte and the police say that figure is exaggerated.
Duterte, who has boasted of personally killing criminals, campaigned for president promising to eliminate drug traffickers. After taking office, he promised to protect police from prosecution for killing drug suspects.
The crackdown was initially popular, but the deaths of three teenagers at the hands of police officers led to public anger and street protests.
Those killings forced Duterte to temporarily put the anti-drug campaign in the hands of the Philippine Drug Enforcement Agency. But in December, he put the police back in charge, saying the drug problem could not be handled by the agency alone. Since then, police have carried out almost nightly raids, and the number of deaths has continued to rise.
The New York Times