MANILA, Philippines — The United States has cautioned claimant countries of the South China Sea from escalating tensions amid reports that Beijing is planning to build a military base or an airstrip on the disputed Mabini Reef.
Marie Harf, US Department of State deputy spokesperson, said they are aware of reports that China is reclaiming land on Johnson Reef called Chigua by China and Mabini by the Philippines.
"Major upgrades or the militarization of disputed land features in the South China Sea by any claimant has the potential to raise tensions," Harf said in a press briefing in Washington, D.C.
The American official's remark came after the Department of Foreign Affairs (DFA) revealed that the Philippines filed a protest against Chinese reclamation on the contested reef, which is part of the Kalayaan Island Group within the Philippine territory.
DFA Sec. Albert Del Rosario earlier said it was not clear what China would build on the reef, but that one possibility was an airstrip. A senior government official had also told the Associated Press that China could also build an offshore military and resupply and refueling hub.
The DFA said the Chinese side rejected the Philippine protest. China's Foreign Ministry spokesperson Hua Chunying, meanwhile, said the disputed reef is completely within their country's territory.
"China has indisputable sovereignty over Nansha Islands including Chigua Reef and the contiguous waters," Hua said in a press briefing.
On Thursday, the DFA released photographs gathered from Philippine intelligence sources, showing in stages the extensive reclamation by China on the reef.
"These actions are considered destabilizing and in violation of the Declaration on the Conduct of Parties in the South China Sea (DOC)," the DFA said in a statement.
The DFA said President Benigno Aquino III raised the issue during the Association of Southeast Asian Nations (ASEAN) Summit held in Myanmar over the weekend.
China and ASEAN member countries in 2002 agreed on the DOC, a non-binding agreement that aims to maintain the status quo and achieve regional stability.
The US said all parties to the DOC should fully and effectively implement it, "especially with regard to exercising self-restraint and the conduct of activities that would complicate or escalate disputes."
"And recent incidents highlight the need for claimants to be transparent about their respective activities in disputed areas," Harf said. -with Jim Gomez, Associated Press