No country can ignore or diminish the arbitral ruling on the South China Sea conflict no matter how big or powerful it is, President Duterte declared Thursday at the start of a virtual regional summit.

The President brought up the country's arbitration victory against China's sweeping claims in the territory when he attended the the Association of Southeast Asian Nations (ASEAN) summit and related meetings via video conference. The arbitration ruling, Duterte stressed, has already become part of the international law.

The Southeast Asian leaders opened the summit organized by Vietnam Thursday with focus on enhancing cooperation to fight the coronavirus pandemic and facilitate regional recovery as well as seeking a peaceful resolution to the territorial conflict.

"The Philippine position is clear and firm. We must solve the disputes peacefully and in accordance with international law, including UNCLOS (United Nations Convention on the Law of the Sea)," Duterte said in his remarks during the ASEAN plenary session.

"The 2016 Arbitral Award on the South China Sea is an authoritative interpretation of the application of UNCLOS. It is now part of international law. And its significance cannot be diminished nor ignored by any country, however big and powerful," he said.

The President also voiced his support for the completion of a Code of Conduct in the South China Sea to promote peace and stability in the region.

"The Philippines is one with ASEAN in transforming the South China Sea into a sea of peace and prosperity for all," he said.

"We are committed to the immediate conclusion of a substantive and effective Code of Conduct in the South China Sea. And if I may add, it has been a long time and it is a long wait," he added.

He admitted that the South China Sea issue remained ASEAN’s strategic challenge. "How we deal with this matter lays bare our strengths and weaknesses as a Community. We must act with haste," he said.

In July 2016, the Permanent Court of Arbitration in the Hague ruled in favor the Philippines in the South China Sea dispute. The tribunal declared that China has no legal basis to claim historic rights within the area falling within its so-called nine-dash line. 

Beijing however refused to recognize the tribunal's decision and pressed ahead with its controversial reclamation works in the disputed territory.

When he addressed the United Nations General Assembly for the first time last September, the President also raised the country's arbitral win in the disputed territory and vowed to reject attempts to undermine it. Duterte said the award has become part of international law "beyond compromise and beyond the reach of passing governments to dilute, diminish or abandon."

In his opening remarks, Vietnam Prime Minister Nguyen Xuan Phuc affirmed the ASEAN’s commitment to promote peace and stability in the South China, recognizing it is a critical sea lane of the region. He said the UNCLOS must remain the framework for the activities in the sea.

He said the bloc wants the South China Sea to "become a region where free flow of goods goes unimpeded, where differences and disputes are settled via peaceful means, where the law is respected and observed, and common values are upheld.”

“As such we expect an early conclusion of an effective and substantive code of conduct in line with international law and the 1982 UNCLOS,” he said.