President Rodrigo Duterte on Saturday equated the pursuit of justice by the Commission on Human Rights chief in connection with the recent series of teenaged murders to being gay and attracted to children.

In a text message to ABS-CBN News seeking his reaction, CHR chair Chito Gascon said the president should "withdraw" the "hurtful language" he issued on national television.

"Itong si Gascon, ilang araw ng puro teenager, teenager, teenager, parang pedophile. Bakla ka or pedophile ka? Iyan lang nakatutok ka," Duterte said in a press conference in Davao City.

Gascon and other human-rights advocates have been denouncing the Duterte administration for a series of killings where police officers allegedly killed innocent teenagers.

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"Teenager ka ng teenager, araw-araw. You are so fixated on the deaths of young males kaya nagdududa ako kung pedophile ka," Duterte said.

The president added that Gascon was attacking his administration because of his affiliation with the Liberal Party.

"He is really a spokesman for the Liberal and for the opposition who want me out of the presidency," Duterte said.

Gascon said Duterte's words were "unfortunate."

"The President again has resorted to name-calling and to using hurtful language against me is unfortunate. I hope he might choose to withdraw them in order to have a common civic space," Gascon's text message read.

"If there may be differences between the positions we take in CHR and that taken by the Executive Branch, we hope this be viewed as part of the checks & balance system of Philippine Democracy," Gascon added.

The CHR chief also denied that he was affiliated with Duterte's political opponents.

"I have not been involved in any partisan activity since being tasked to perform human rights programs first with the human rights victims claims board in 2014 & assuming my leadership of the CHR," Gascon said.

"I have taken an oath of office that mandates me to focus only on our human rights work without fear or favor. I have not nor will not participate in any destabilization of the state or any other action that would undermine our democratic system."