China warned Asian neighbors on Thursday to stop searching for oil near the disputed Spratly Islands and vowed to assert its sovereignty over the potentially petroleum-rich territory in the South China Sea despite rival claims.

At the same time, however, China gave assurances Beijing would assert its right over the disputed region diplomatically. “We will never use force, unless we are attacked,” Chinese Ambassador to Manila Liu Jianchao told reporters.

China also frowned on proposals that outsiders, notably the United States, a close ally of the Philippines, be included in efforts to resolve the problem peacefully. It said it would only discuss the dispute bilaterally with other claimant-countries.

“The US is not a party to the disputes,” Liu said bluntly.

China and the Philippines have swapped diplomatic protests over the islands, with Filipino officials accusing Chinese forces of intruding into Manila-claimed areas six times since February and of firing shots in at least one incident. Beijing denied the allegation on Thursday and said it would use violence only when attacked.

The Spratlys, which are believed to be atop vast oil and gas reserves, have long been feared as a potential flash point of armed conflict in Asia. The chain of barren, largely uninhabited islands, reefs and banks, are claimed wholly by China, Taiwan and Vietnam and partly by the Philippines, Malaysia and Brunei.

Addressing Manila’s complaints for the first time on Thursday, Ambassador Liu denied his government committed any intrusion.

He said China has not started to drill for oil in the contested region and warned other claimants to stop any oil-exploration in the Chinese-claimed area without Beijing’s permission. China claims the entire South China Sea.

Liu didn’t mention specific companies.

The Philippines, however, insists that it has “unequivocal sovereign rights” over the Reed Bank basin, about 595 nautical miles from China and 85 miles from the Philippines, putting it “well within” the latter’s continental shelf, according to Foreign Secretary Albert F. del Rosario.

The Reed Bank is where the UK’s Forum Energy Plc. has been operating and this has been cleared by the Department of Energy (DOE).

In March the London-based oil-and-gas company said it is in discussion with potential joint-venture partners for Service Contract (SC) 72 under the Sampaguita gas block in west Palawan. SC 72 covers 880,000 hectares and is located in the Reed Bank basin.

Robin Nicholson, Forum executive chairman, had said seismic studies are currently being undertaken on SC 72, or formerly Geophysical Survey Exploration Contract 101. The studies are expected to be completed by this quarter.

Forum said it implemented the first subphase work program, which is estimated to cost approximately $7.4 million. This is designed to provide a more comprehensive evaluation of the SC 72 property and to identify potential sites for appraisal wells.

But on Thursday, Liu told reporters: “We’re calling on other parties to stop searching for the possibility of exploiting resources in these areas, where China has its claims.”

But he said China was open to engaging other claimant-countries in jointly exploring for oil and gas in the region.

This isn’t the first time the idea of joint exploration was broached.

In 2005 the Philippine National Oil Co. (PNOC), the China National Offshore Oil Co. and PetroVietnam agreed to conduct a joint marine seismic undertaking (JMSU) over the Spratlys. But this expired in 2008 and was never extended or renewed.

That joint exploration covered an area of 142,886 square kilometers for seismic study. Previous officials of the PNOC and the DOE even considered the JMSU a big step toward transforming a previous area of conflict into an area for possible cooperation and mutual benefit.

The agreement was designed to be commercial in nature and does not affect territorial claims of the respective countries of the area. Under Article 6 of the JMSU, pending a comprehensive and durable settlement of the disputes, the parties concerned may explore or undertake cooperative activities.

Then-Energy secretary Vincent Perez said this was supported by the Philippine government to promote regional energy security.

“The government also hoped the JMSU to contribute to the transformation of the South China Sea into an area of peace, cooperation and development, which was part of a strategic alliance to promote regional energy security, to lessen the region’s dependence on Middle East oil,” Perez said at the time.

In the most serious incident reported by the Philippines, Chinese navy vessels allegedly fired shots on February 25 to scare away Filipino fishermen from Jackson Atoll, which is claimed by Manila and relatively close to Philippine shore.

The Philippine government also accused two Chinese patrol boats of harassing a Filipino oil-exploration ship on March 2 into leaving a vast area called the Reed Bank. A Filipino general scrambled two military aircraft, which arrived after the Chinese vessels had left, the Philippine military said.

Liu said no Chinese vessel fired on Filipino fishermen but suggested that Chinese forces took action to keep the Filipino exploration ship from the Reed Bank.

“That’s part of our exercise of jurisdiction. It’s not harassment,” Liu said.

Liu, however, confirmed the deployment of marine surveillance vessels in the Spratlys but clarified it does not plan to establish military presence in the contested region.

“We have no intention of occupying one of the islands,” the Chinese envoy stressed. “We clarified that those materials were intended for surveys in the area.”

Filipino diplomatic experts on the South China Sea dispute believe that the Chinese activities may be connected with China’s plan to conduct deep-sea mining in the Indian Ocean, which is pending approval before the United Nations.

Liu also dismissed concerns raised by the United States that the dispute over the Spratlys could hamper the passage of commercial ships in the South China Sea. Liu said the area would remain peaceful.

The tug-of-war between China and the Philippines over the islands has raised questions about a role Washington could play to help solve the dispute and keep some of the world’s busiest sea lanes open and secure.

David Carden, Washington’s ambassador to the Association of Southeast Asian Nations (Asean), said last month in Manila that the Spratly claimants need to create a strong regional mechanism to tackle the dispute. He said the US can help.

China, however, would only discuss the dispute bilaterally with other claimant-countries, Liu said.

“The US is not a party to the disputes,” he said. “These maritime waters have always been peaceful and secure.”

The Chinese government insists its sovereign right and jurisdiction over the South China Sea territory date back to the Tang Dynasty, or during the 7th century.

Liu noted that China’s claims over the South China Sea have not been contested until after World War II and the early 1970s.

But he said Beijing remains committed to the Declaration of Parties in the South China Sea (DOC) signed between China and Asean in November 2002 that seeks to maintain status quo in the disputed region. The accord also prevents parties from engaging in military activities that will affect peace and stability in the disputed region.

“Peaceful means is the only option for China and we are determined to carry on with peaceful consultation with our partners, our neighbors, who are also claiming the Nansha Islands,” Liu said, using the Chinese name of the Spratlys.

He also stressed that marine surveillance presence in the dispute South China Sea did not violate the DOC, saying “everything was carried out within the sovereignty of China.” 

He said survey activities are normal and allowed by the DOC. “We don’t really believe that it’s a breach of the DOC. It conforms with the spirit of the DOC,” Liu said.

“I don’t want the Nansha issue to be a barrier in our generation. I think this view is also shared by my colleagues in the DFA [Department of Foreign Affairs],” Liu added.