Metro Manila (CNN Philippines, March 16) — The Philippines has formally sent a letter of withdrawal from the Rome Statute, the treaty that governs the International Criminal Court (ICC).

Philippine Permanent Representative to the United Nations (UN) Teddy Boy Locsin posted the letter on his Twitter account, which he delivered to UN Chef de Cabinet Maria Luiza Viotti Thursday evening.

"The decision to withdraw is the Philippines' principled stand against those who politicize and weaponize human rights, even as its independent and well-functioning organs and agencies continue to exercise jurisdiction over complaints, issues, problems and concerns arising from its efforts to protect its people," the letter read.

The letter also stated the country is committee "to fight against impunity for atrocity crimes."

"The Philippines assures the community of nations that the Philippine Government continues to be guided by the rule of law embodied in its Constitution, which also enshrines the country's long-standing tradition of upholding human rights," it stated.

Locsin added on his Twitter post: "It is my duty to give you this. A sad day but a day sure to come because human rights has been politicized. We resisted US pressure not to join until we finally signed on only to have it weaponized against our democracy fighting an existential threat from the drug trade."

President Rodrigo Duterte announced the country's withdrawal "effective immediately" on Wednesday, March 14. He slammed the preliminary examination of ICC prosecutor Fatou Besouda against the country's war on drugs, and the "international bias" of UN Special Rapporteur Agnes Callamard and UN High Commissioner on Human Rights Zed Ra'ad al-Hussein against the human rights situation in the country.

Earlier, the ICC clarified that their preliminary investigation, which was announced in February, was only a process of determining whether there is sufficient basis to continue with an actual investigation. ICC conducted the probe in response to a communication filed by Atty. Jude Sabio in April 2017.

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 war on drugs since Duterte took office.