Metro Manila (CNN Philippines, March 14) — Amid criticism from local and international groups, the Palace on Wednesday justified its pending move to withdraw the Philippines' membership from the International Criminal Court (ICC).

Presidential Spokesperson Harry Roque told CNN Philippines that the ICC has no jurisdiction over the Philippines because the country's ratification of the Rome Statute was not published on the Official Gazette.

"This is a penal law, and should be published pursuant to the ruling of the Supreme Court...What the Court says is the provisions of a penal law be published so the people will know exactly what is being punished by the treaty," Roque said.

Roque cited the Supreme Court ruling in the 1985 case of Tañada vs. Tuvera, which stated "this Court has ruled that publication in the Official Gazette is necessary in those cases where the legislation itself does not provide for its effectivity date."

The President's spokesperson came to Duterte's defense after various international groups slammed the move to pull out from the ICC.

Commission on Human Rights Chairperson Chito Gascon said government is "grossly mistaken" that the ICC does not have jurisdiction over events in the country.

"The government must show good faith by fully cooperating with ICC processes including the current preliminary examination which can not be terminated by this withdrawal," Gascon said on Wednesday.

International organization Human Rights Watch (HRW) said they were not surprised by Duterte's move, as he has showed disregard for the rule of law.

"Duterte has long showed disdain for the rule of law. Last August, Duterte vowed to pardon and promote - rather than punish - any police officer who carried out an unlawful killing. His announcement to pull out of the ICC, which is designed to prosecute those most responsible for grave crimes, is a barefaced attempt to shield him and high-ranking officials from possible ICC prosecution," HRW said in a statement.

Some lawmakers from both houses of Congress also questioned the withdrawal. However, Senate President Aquilino "Koko" Pimentel said the Senate has no say on the matter, as the legislative body's concurrence on the withdrawal is not required.

"Wala [None]. That's why dito sa new treaties we are ratifying, meron kaming provision na nilalagay that withdrawal will require 2/3 (of the Senate)," Pimentel said in a message.

The Philippines signed the Rome Statute of the ICC in 2000 and ratified it in 2011, becoming its 117th State Party.

Roque was a former co-chairperson of the Philippine Coalition for the International Criminal Court, which lobbied for the Philippines to ratify the Rome Statute and become an ICC member.

The spokesperson added the country will comply with all the proper procedures in withdrawing from the ICC.

READ: Duterte: PH to withdraw from ICC 'effective immediately'

Principle of complementarity violated?

The ICC, an intergovernmental organization that investigates cases of genocide, war crimes, crimes against humanity, and crimes of aggression, was established by the Rome Statute, which was created in 2002.

It was meant to be a court of last resort when local courts of its state parties are incapable or unwilling to act on such matters.

The ICC earlier announced it would begin preliminary examination on the administration's controversial war on drugs.

The preliminary examination is not an investigation, the ICC said, but a process to see if there is basis to proceed with an investigation.

Roque, who called the international tribunal "useless," said ICC Prosecutor Fatou Bensouda violated the court's principle of complementarity by initiating a preliminary examination.

"Because the prosecutor herself violated the principle upon which we agreed to become a member of the court, it is justified for the country to withdraw," he said.

Roque also discredited the merits of the crime against humanity lodged against the administration's drug war before the ICC.

"On the merits, one of the elements of the crime against humanity is murder, which is the crime of unlawful killing, and that any killing in connection with the drug war could not be unlawful killing because they are valid, legitimate police action," Roque said.

He also slammed the ICC for acting on "flimsy complaints filed by politicians."

The ICC is looking into the drug war after lawyer Jude Sabio filed a communication in April 2017. Sabio is the lawyer of self-confessed hitman Edgar Matobato, who said he killed people in Davao City upon the orders of then then-Mayor Duterte.

Sabio accused Duterte of "repeatedly, unchangingly, and continuously" committing mass murder. He said 1,400 individuals were killed by the so-called Davao Death Squad under the leadership of then Mayor Duterte, and 7,000 individuals were killed in the government's war on drugs since Duterte took office.

Senator Antonio Trillanes IV and Magdalo party-list Rep. Gary Alejano also filed a supplemental complaint against Duterte at the ICC in June 2017. They are two of Duterte's strongest critics.