MANILA (2nd UPDATE) - Filipino fishermen and former government officials have filed a complaint against Chinese President Xi Jinping before the International Criminal Court (ICC) for crimes allegedly committed in the disputed South China Sea.

Xi and other Chinese officials allegedly committed crimes against humanity in implementing Beijing's "systematic plan to control the South China Sea."

"The situation is both unique and relevant because it presents one of the most massive, near permanent and devastating destruction of the environment in humanity's history," the complainants said.

"It adversely affects and injures not only myriad groups of vulnerable fishermen, including 320,000 Filipino fishermen, but also present and future generations of people across nations," the group said in a statement.

Former Foreign Affairs Secretary Albert del Rosario and former Ombudsman Conchita Carpio Morales joined the fishermen in filing the communication to the ICC on March 13.

"Though widely publicized, these atrociously inhumane actions of Chinese officials in the South China Sea and within Philippine territory remain unpunished, and it is only the ICC that can exact accountability on behalf of Filipinos and the international community, respecting the rule of law," they said.

Among crimes punishable under the ICC are genocide, crimes against humanity, war crimes, and aggression.

China is not a state party to the Rome Statute, which established the ICC.

The Philippines effectively withdrew from the international body last Sunday, March 17, after President Rodrigo Duterte unilaterally decided to pull out amid its preliminary examination into his administration's war on drugs.

The ICC, which received the communication on March 15, has jurisdiction over crimes committed during the period the Philippines was a member of the international body from Nov. 1, 2011 to March 17, 2019, the group said.

It was during Del Rosario's time as top Philippine diplomat that the country brought China before a United Nations-backed arbitral tribunal in 2013 for incursions in the country's exclusive economic zone within the disputed South China Sea.

The tribunal, based in The Hague, invalidated China's 9-dash line claim over the waters and recognized traditional fishing rights of Filipinos in the Scarborough Shoal, an area where Beijing's patrol ships had shooed away Philippine fishermen.

The Philippines and China have long sparred over the South China Sea, but relations have improved considerably under Duterte, who set aside the 2016 landmark legal victory for enhanced ties.

Duterte, meanwhile, said the group is "entitled to file the case."

"They are Filipino citizens and I think we'll just have to defend our position vis-a-vis sa kanila," he told reporters in a chance interview at the Philippine Army's 122nd Founding Anniversary rites.

China has assured the Philippines it would not occupy new features or territory in the South China Sea, under a new "status quo" brokered by Manila as both sides try to strengthen their relations.

Vietnam, the Philippines, Brunei, Malaysia, Indonesia, and Taiwan have overlapping claims in the South China Sea.