Second, the country's withdrawal from the ICC does not absolve it from its unfulfilled obligations and from crimes committed while it was still a signatory.
He said the withdrawal was due to "baseless, unprecedented and outrageous attacks" by United Nations officials, and the ICC not following due process and the presumption of innocence.
In a television interview also on Friday, Palace spokesman Harry Roque, Jr. said that it was already too late to back out of the withdrawal because "the train has already left".
He reiterated that Duterte was willing to face the allegations against him but the ICC had no jurisdiction over him.
"The government affirms its commitment to fight against impunity for atrocity crimes, notwithstanding its withdrawal from the Rome Statute, especially since the Philippines has a national legislation punishing atrocity crimes", the government said in a letter dated Thursday and addressed to the United Nations secretary-general.
"It is doubly lamentable that members of the global community, who include our own partners in the war against terror, have allowed themselves to be used as pawns by these individuals and organizations in undermining our own efforts to restore the rule of law", Cayetano added.
"Duterte's statement highlights the urgent need for a UN-led investigation into the drug war killings", Singh said, adding that an inquiry would add worldwide pressure on the Philippine government to stop the killings.
The ICC's initial review of the alleged human rights violations linked to the Philippines' fight against illegal drugs was based on the communications lodged by lawyer Jude Sabio, and opposition lawmakers Senator Antonio Trillanes IV and Gary Alejano.
If anything, it may embolden the ICC to take a tougher stance and move ahead with prosecution of specific officials.
Roque added that the President was not avoiding a possible indictment from the ICC.
Duterte has insisted that the ICC has no jurisdiction over him.
And last month, as the ICC announced its preliminary inquiry, the UN Human Rights Council questioned the Philippines' human rights record and called on the country to accept a UN special rapporteur.
Foreign Secretary Alan Peter Cayetano said the move was a "principled stand".
He also said he would "love" to be executed by firing squad if found guilty by the ICC.
Ms Bensouda first said she was "deeply concerned" about reports of extrajudicial killings in October 2016, less than four months after Mr Duterte assumed office on a pledge to crack down on drug dealers.
Lagman said Duterte "cannot overcome overwhelming evidence against him consisting of his own incriminating utterances of instigation and condonation, and unassailable records of extrajudicial killings consequent to his deadly war on drugs".
Duterte's opponents wasted no time in accusing him of flip-flopping, pointing out that he had repeatedly dared the ICC to indict him and said he would "rot in jail" to defend a war on drugs during which police have killed thousands of people.
Under Article 127 of the Rome Statute, a state party's withdrawal from the treaty can only take effect a year after the written notification is received by the UN Secretary-General. "Neither is it a crime of aggression or a crime against humanity", he said.