Abella said that the war on drugs "are within the our ambit of national sovereignty, national concerns, and that at this stage there was no call for the UN to make any investigations."

"If there would be serious intentions about investigating these matters they should have made formal presentations and not just made general statements. The UN as a public institutions should have made formal representations because we also are a formal institution," Abella said.

Meantime, a member of the House of Representatives slammed Duterte's threat to withdraw the Philippine membership in the UN, saying the Duterte's action is "impulsive, imprudent, and contrary to the interests of the nation."

"To turn away from such the community over a series of internal affairs would be truly regrettable. Withdrawal from the UN is not something that should be taken lightly for it could bring about disastrous consequences for the country," Rep. Harry Roque said.