A 2016 ruling by a United Nations (UN) tribunal rejecting China’s claim to more than 80% of the South China Sea is nonnegotiable, according to the Philippines’ top diplomat.

“Compliance in good faith with the award would be consistent with the obligations of the Philippines and China under international law,” Foreign Affairs Secretary Teodoro L. Locsin, Jr. said in a statement on Sunday.

“The Philippines, as a law-abiding, peace-loving and responsible member of the international community, reaffirms on this occasion its adherence to the award and its enforcement without any possibility of compromise or change,” he said. “The award is non-negotiable.”

The Department of Foreign Affairs issued the statement on the fourth anniversary of the decision favoring the Philippines in the arbitration case filed by the government of then President Benigno S.C. Aquino III.

The tribunal ruled that China’s claim of historic rights to resources within the sea falling within the ‘nine-dash line’ was illegal. “Claims to historic rights, or other sovereign rights or jurisdiction that exceed the geographic and substantive limits of maritime entitlements under UNCLOS, are without legal effect,” Mr. Locsin said in the statement.

The court said the Philippines could declare certain sea areas part of its exclusive economic zone because these areas do not overlap with any entitlement claimed by China.

Certain actions within the Philippines’ exclusive zone violated its sovereign rights and were unlawful, the court said. It added that China’s island-building activities in the disputed waterway had caused severe environmental harm in violation of international conventions.

President Rodrigo R. Duterte has sought closer trade and investment ties with China since he took office in 2016, including potential joint explorations for oil and gas in the South China Sea. — CAT