Commission on Human Rights chairman Chito Gascon said Saturday that his agency is ready to work with the International Criminal Court as it investigates the thousands of killings linked to the government's campaign against illegal drugs.

Gascon also urged the police and justice department to cooperate with the ICC in its "preliminary examination" into whether President Rodrigo Duterte has committed a crime against humanity in conducting the crackdown on drugs.

ICC prosecutor Fatou Bensouda announced earlier this week that her office would analyze the alleged crimes carried out since July 1, 2016.

• ICC prosecutor seeks PH gov't cooperation on crimes examination

"The CHR is ready, if requested, to assist in any way with the process of preliminary examination. The government, as a party to the Rome Statute, is duty-bound to fully cooperate with the ICC," Gascon said in a statement.

His comments came after Duterte on Friday declared himself beyond the jurisdiction of the probe, saying that while a previous administration had ratified the treaty establishing the ICC it had not become local law because of a technicality.

• Duterte unfazed by ICC review of drug war

Gascon's commission has also sought to investigate the illegal-drug war killings but has been hampered by a lack of cooperation from other government agencies such as the police as well as limited resources.

Angered by the commission's criticism of Duterte's drug war, the president's congressional allies last year tried to slash its budget to just P1,000 until a public outcry forced them to reverse the move.

• House votes for only P1,000-budget for CHR

The ICC's initial inquiry is designed to help prosecutors determine if there is enough evidence of crimes that fall into its jurisdiction. It could lead to a full probe and eventually charges.

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