Chinese officials in Beijing are warning against any joint military patrols or exercises between Vietnam and the Philippines in the disputed South China Sea. 

Vietnam and Philippines military officials have discussed conducting joint exercises in the disputed region in meetings earlier this month. The exercises could include joint patrols of the Spratly Islands, which both countries and China claim as their own.

In Beijing, Foreign Ministry spokesman Hong Lei warned against any exercises in the Spratlys, which China calls Nansha.

China has indisputable sovereignty over the Nansha Islands, he said, and the adjacent waters. Hong also said China is opposed to foreign countries’ violation of China’s sovereign rights and interests.

There have been a series of run-ins involving fishermen, military patrols, and other vessels in the disputed region in recent months, increasing tension over the competing territorial claims. Philippine and Vietnamese officials have discussed establishing a communication hotline for possible disputes, as well as sharing shipbuilding expertise.

A visiting professor at the National University of Singapore, Huang Jing, a China foreign policy analyst, said Beijing is unlikely to back down on its claims to the resource rich waters.

“China is getting stronger and stronger, the so called peaceful rise, and the rise of nationalism in China on the one hand, and also the increasing demand for external resources and the market so all of a sudden the territory dispute in the South China Seas has become a kind of priority in the policy discussion and internal debate,” Huang Jing said.

China, Vietnam, the Philippines, Malaysia, Brunei and Taiwan all claim South China Sea territories. China has claimed the largest portion of territory

The various claims are expected to be on the agenda during Chinese President Hu Jintao’s visit Friday to Cambodia. The country is the head of the 10 member Association of Southeast Asian Nations, and Philippine officials have said they are frustrated by Chinese efforts to block discussion of the South China Seas issue in the organization.

China’s Foreign Ministry spokesperson said the focus of Hu Jintao’s visit will be strengthening China’s ties to Cambodia, where Chinese investment has grown rapidly in recent years.

China hopes through this visit China-Cambodia friendly relations and cooperation will be promoted, practical cooperation will be deepened and people to people exchanges will be enhanced, said Hong. He added that Beijing hopes for greater coordination in international and regional affairs.
China says its territorial claims in the South China Sea stem from 2,000 years of history when the Spratly Islands were an important part of China. Vietnam says China did not lay claim to this territory until the 1940s. 

The contested waters are rich in oil and natural gas reserves and serve as one of the busiest shipping lanes in Asia.