Beijing hit out on Tuesday at reports that the Philippines has built a military shelter in a contested island chain in the South China Sea, warning Manila to expect "consequences."
Citing a report in the Philippine Star newspaper on Sunday, the People's Daily, mouthpiece of the ruling Communist Party, slammed the structure which was reportedly nearing completion on the Nansha Island chain, which China claims as its territory.
"The Philippine Navy is about to finish construction of a second star shell-like structure on an islet in the Nansha [Spratly] Islands area, over which China has territorial sovereignty," said the signed commentary.
"This action is a serious violation of the Declaration on the Conduct (DOC) of Parties in the South China Sea," the article said, citing a 2002 agreement between several countries claiming contested territory in the oil-rich shipping lanes around the Spratly and Paracel island chains.
The newspaper report said the structure is designed to shelter and protect troops guarding the Philippines' interests in the disputed maritime region.
It said proposals by the Philippines at a recent Association of Southeast Asian Nations (ASEAN) security forum to make the disputed area into "a zone of peace, freedom, friendship and cooperation," were "just a trick."
"The country clearly lacks sincerity in solving the dispute in a peaceful way," the commentary said.
"The move of the Philippine side in violating the DOC and undermining future cooperation should be strictly restrained," it added.
The warning follows the inking of a pact last month between China and its ASEAN neighbors aimed at governing conduct in the disputed waters, based on the 2002 code.
Tensions have risen in recent months around the disputed Spratly and Paracel island chains, claimed in their entirety by China, Taiwan, and Vietnam and in part by the Philippines, Malaysia, and Brunei.
A wider accord on which country owns what remains elusive. The issue has heated up in recent months with several incidents between claimants, particularly involving China.
The guidelines adopted by Beijing and ASEAN sets out agreed measures to make the 2002 DOC of Parties in the contested South China Sea more binding.
Vietnam and China have held separate live-fire military exercises in the disputed maritime region near the Spratly and Paracel island chains after Hanoi accused Chinese ships of ramming one oil survey ship and cutting the exploration cables of another.
Hanoi also said sailors from China's navy had beaten the captain of a Vietnamese fishing boat and confiscated its catch.
The standoff sparked a wave of anti-China protests in Vietnam and warnings from Beijing to Vietnam not to try to involve the United States.
Last month, Vietnam and the United States carried out joint naval exercises in spite of disapproval from China.
China has underlined its "indisputable sovereignty" over the South China Sea, saying its claims stretch back at least to the 1930s, when official maps from Beijing contained the whole sea as Chinese territory.
Beijing has also rejected calls by ASEAN states for arbitration by the U.N.'s International Tribunal for the Law of the Sea, an independent judicial body set up by the Convention of the Law of the Sea, the global legislation covering all maritime territorial disputes.
It has also unveiled a map showing a U-shaped dotted line extending from China and enclosing virtually the entire South China Sea while hugging the coastline of Vietnam, Malaysia, Brunei, and the Philippines.
Reported by Luisetta Mudie.