China on Monday warned the Philippines against its plan to create its own code of conduct for the South China Sea with other members of the Association of Southeast Asian Nations.

In a press briefing, Chinese Foreign Ministry spokesperson Mao Ning underscored that the creation of the Declaration on the Conduct of Parties in the South China Sea is an "important task" for China and ASEAN countries.

Mao, however, stressed that "any departure" from the DOC framework and its spirit would "be null and void."

China's response stemmed from President Ferdinand Marcos Jr.'s announcement on Monday that the Philippine government has started negotiating with other ASEAN members such as Vietnam and Malaysia to formulate a separate COC.

Citing the "more dire" situation in the South China Sea which includes the West Philippine Sea, Marcos said the Philippines took the initiative to discuss the matter with ASEAN members that are also claimant states in the disputed areas.

"We are now in the midst of negotiating our own Code of Conduct for example with Vietnam, because we are still waiting for the Code of Conduct between China and ASEAN, and the progress has been rather slow unfortunately," Marcos said.

Four of the ten members of the ASEAN are primary claimants of the resource-rich South China Sea such as Vietnam, Malaysia, the Philippines, and Brunei.

Grounded in history

China also rejected Marcos' accusation that its construction and reclamations in the South China Sea for its military bases have come "closer and closer" to the Philippines' coastline.

"China's position and claims concerning the South China Sea issue are solidly grounded in history and the law," Mao said.

"China carrying out construction activities on its own territory is a matter purely within the scope of China's sovereignty and other countries have no right to point fingers at it," she added.

China claims the vast South China Sea, including the West Philippine Sea, which is within the Philippines' 200-nautical mile EEZ.

In 2016, the Permanent Court of Arbitration rejected Beijing's historical claims in the West Philippine Sea and favored Manila's sovereign rights in the area.

Despite this, the 2016 Arbitral Award on the South China Sea remains on paper as China has continued to reject the ruling and assert its claim in the area.

Last week, the Philippines' Department of Foreign Affairs lambasted China over its recent statement that accused the Philippines of expanding its military post in Ayungin Shoal, which they also claimed and referred to as Ren'ai Jiao.

In a strongly worded statement, the DFA urged China to remove all of its illegal militarized artificial islands and cease its reclamation activities in the West Philippine Sea.

"We call on China to remove all these illegal structures, cease reclamations in the South China Sea, and be accountable for the damages caused by these illegal activities," the agency said, responding to Chinese Foreign Ministry spokesperson Wang Wenbin's recent statement.

It stressed that the rotation and resupply mission of the Philippines, including the maintenance of the BRP Sierra Madre, are "legitimate activities" of the government within its 200-nautical-mile exclusive economic zone.

It added that the resupply mission is in accordance with international law, particularly the United Nations Convention on the Law of the Sea, to which China is a signatory party.

The DFA also took a swipe against China for accusing the Philippines of bringing construction materials to the grounded BRP Sierra Madre, which was deliberately stationed in Ayungin Shoal in 1999 to "serve as a constant Philippine government presence in response to China's illegal occupation in 1995 of Panganiban Reef, also known as Mischief Reef."

"Panganiban Reef is a low-tide elevation that forms part of our continental shelf and is within our EEZ. You may all recall that in 1995, when we protested China's construction of a structure in Mischief Reef, China promised that it was only a 'fisherman's shelter' and would remain as such," it said.

"The reef is now a militarized artificial island. So are Calderon Reef, also known as Cuarteron Reef; Kagitingan Reef, also known as Fiery Cross Reef; Burgos Reefs, also known as Gaven Reefs; McKennan Reef, also known as Hughes Reef; Johnson Reef; and Zamora Reef, also known as Subi Reef. Let us not forget that," it added.