Metro Manila (CNN Philippines, June 24) — Retired Supreme Court Senior Associate Justice Antonio Carpio, a critic of the Duterte administration, supported the Philippine governments decision to end the joint oil and gas exploration pact it inked with China.

Despite China refusing to acknowledge the Philippines arbitral win on the West Philippine Sea, the two nations signed an agreement in 2018 to conduct research for natural resources in the contested waters in accordance with international law.

Carpio on Friday backed the Philippines decision, saying China attempted to tweak the signed memorandum of understanding (MOU) and terms of reference (TOR) when it demanded to change the framework of the Service Contract System of the Philippines.

The former magistrate said China sought to delete two crucial portions in the Service Contract System which states that the oil and gas belong to the Philippines and that Philippine law will govern the contract.

"We won the first two rounds — the signing of the MOU and the TOR. China tried to reverse the situation by demanding the deletion of the two provisions. Of course we could not agree to that. That is why China walked away in the third round," he said in a text message.

Carpio said that if the administration of President Rodrigo Duterte folded to pressure from China, it would have been be a violation of the 1987 Constitution and it would signify that the Philippines is abandoning the landmark arbitral win which recognized the Philippines sovereign rights to areas within its exclusive economic zone that China contests.

Outgoing Foreign Affairs Secretary Teodoro Locsin Jr. on Thursday revealed that Duterte ordered the full termination of the deal.

"Three years on and we had not achieved our objective of developing oil and gas resources so critical for the Philippines but not at the price of sovereignty; not even a particle of it," he said.

Prior to Duterte and Chinese President Xi Jinping signing the agreement, a moratorium on oil exploration in the West Philippine Sea was implemented by Dutertes predecessor Benigno Aquino III due to Chinas encroachment in local waters.