MANILA - Several rights groups on Wednesday said proceedings at the International Criminal Court (ICC) on charges filed against President Rodrigo Duterte over deaths in his drug war would continue despite his decision to withdraw the country's ratification of the treaty that created the tribunal.

In a statement, the Commission on Human Rights (CHR) said the government's withdrawal from the international court does not terminate the ICC's ongoing preliminary examination.

• PH to withdraw from ICC

"The government must show good faith by fully cooperating with ICC processes including the current preliminary examination which cannot be terminated by this withdrawal," the agency said in a statement.

"The government is grossly mistaken in believing that the ICC does not have jurisdiction over events in this country. What it must do is to show that it is willing and able to bring all perpetrators of human rights violations to justice," it said.

Chief Presidential Legal Counsel Salvador Panelo announced earlier Wednesday that the President had ordered the withdrawal of the Philippines' ratification of the Rome Statute, which created the ICC. The pullout is "effective immediately," he said.

This amid the court's preliminary examination of charges against the President, among them crimes against humanity for alleged abuses under his fierce anti-narcotics campaign.

With the move, the administration expects the ICC to no longer have jurisdiction over the chief executive.

• Palace: ICC to start ‘preliminary examination’ into 'crimes against humanity' charges vs Duterte

Rights Group Amnesty International said the Philippines "cannot avoid its obligations by withdrawing from the Rome Statute."

"...The OTP (Office of the Prosecutor) would not be precluded from opening an investigation even if the Philippines withdrew from the Rome Statute, and Amnesty International believes that the Philippines would also remain under a continuing obligation to cooperate with the Court even if it withdrew from the Rome Statute," it said.

"Crucially, withdrawal from the Rome Statute does not extinguish the Philippines government’s obligations to put an end to human rights violations, and to provide measures for accountability for any crimes committed."

Human Rights Watch, meanwhile, said the Duterte administration may still face prosecution from the ICC for crimes committed in the Philippines while it was still a member-state.

"The Philippines’ intention to walk away from the ICC is unfortunate, but it doesn’t shut the door on the prosecutor’s scrutiny of the government’s horrendous track record of grave abuses. Those responsible for ICC crimes committed in the Philippines while the country is still a member could find themselves facing justice in The Hague," it said.

Former Solicitor General Florin Hilbay said Duterte "has no authority to withdraw from the ICC on his own."

"The ICC was ratified by the Senate. Withdrawal, as a constitutional matter, requires a similar concurrence," Hilbay said in a tweet.

"Also, withdrawal from ICC takes effect 1 [year] after notification & [without] prejudice to any pending matter."

Pres. Duterte has no authority to withdraw from the ICC on his own. The ICC was ratified by the Senate. Withdrawal, as a constitutional matter, requires a similar concurrence.

Also, withdrawal from ICC takes effect 1 yr after notification & w/o prejudice to any pending matter. pic.twitter.com/ATGTAGIekt

— florin hilbay (@fthilbay) March 14, 2018

Lawyer Abdiel Fajardo, president of the Integrated Bar of the Philippines, echoed the sentiment and said: "An important national decision such as the country withdrawing from the Rome Statute should undergo the same scrutiny, diligent study, and debate that the country's prior decision of entering into the Rome Statute went through."

Lawyer Edre Olalia, President of the National Union of People’s Lawyers, called the move "a cop out."

"It jumps the gun on his potential legal liability or responsibility. He wants to be immune and act with impunity both under domestic law and under international law," he said.

"The legal reasoning and factual narrative of the withdrawal are novel at best and skewed at worst. The bases and protocol for the withdrawal are either premature, assumes a fact not established, conclusory or inapplicable. They are patently self-serving and unilaterally rearranges the cosmos of international law and its principles."

The case against Duterte was filed by Jude Sabio, lawyer of confessed hitman Edgar Matobato who earlier tagged the President in extrajudicial killings.

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Duterte, a former prosecutor, had said the ICC could not have jurisdiction over him.

The administration has many times denied involvement in summary killings, saying the nearly 4,000 drug suspects killed in police operations had put up violent resistance.

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Created in 1998 through the Rome Statute, the ICC has jurisdiction over 124 of its members, including the Philippines.

The Philippines signed the Rome Statute on December 28, 2000 and ratified and endorsed it on August 30, 2011, during the time of Duterte’s predecessor, then President Benigno Aquino III.

The ICC is the first permanent institution having power to exercise jurisdiction over persons for the most serious crimes of international concern such as genocide, crimes against humanity, war crimes and crimes of aggression, and is seen to help end impunity for the perpetrators of these crimes.