The ICC is the world's only permanent war crimes court and aims to prosecute the worst abuses when national courts are unable or unwilling, which was opened in 2002.
The country's withdrawal from the Rome Statute, the treaty that established the International Criminal Court, should take effect one year after written notification of the withdrawal is received by the UN Secretary-General.
He said the United Nations expert on extrajudicial killings, Agnes Callamard, had without any proof "pictured me as a ruthless violator of human rights" who was directly responsible for homicide.
Police claim they have killed around 4,000 drugs suspects but rights groups suggest the figure could be far higher, up to around three times the number.
Chafing at the "baseless, unprecedented and outrageous attacks on my person", Mr Duterte said in a statement that he was serving notice that the Philippines was withdrawing its ratification of the Rome Statute.
Duterte insists the deaths have occurred as police acted in self-defense against suspected drug offenders.
Publicly declaring in speeches that a country will withdraw will not automatically jumpstart the process.
Is Philippines member of ICC? .
"I imagine this will be an worldwide embarrassment for the Philippines", said Hilbay, remarking that the country had once been seen as a regional leader in human rights.
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Duterte has been threatening to pull out of the Hague-based worldwide tribunal since the start of his presidential term in mid-2016. He has refused to accept some police may be systematically executing suspected dealers, as activists say.
Last month, he indicated he would cooperate with the ICC examination and even said he would prefer a firing squad to prison.
"Also, we can not get out of ICC jurisdiction just like that".
The Hague-based tribunal announced last month that it had opened a preliminary examination of a complaint filed past year by a Philippine lawyer over the president's anti-drug campaign, which has left 4,000 dead since Duterte took office in 2016. However, the 72-year-old said that he is not planning to wait, and that the withdrawal would take place immediately.
But Article 127 of the Rome Statute also explicitly says that criminal investigations and proceedings that have been started before the withdrawal came into effect will still continue.
Duterte had previously said the Philippines had never fully ratified the statute that makes it a member of the ICC.
Baguilat hopes that Presidential Spokesperson Harry Roque Jr., a former human rights lawyer who had pushed for the ratification of the Rome treaty, can provide better advice to the President.
Mallari, the law professor, said the ICC might decide that the Philippine justice system is not working properly because the key agencies are under control of close allies of Duterte.
"President Duterte's withdrawal from the Rome Statute is meant to escape accountability by present and even future officials for crimes committed against the people and humanity".