BEIJING — The Chinese navy conducted three days of exercises — including live-fire drills — in the disputed waters of the South China Sea this week, escalating tensions over a potentially resource-rich area also claimed by some neighboring countries in southeast Asia.
The display of Chinese naval might hundreds of miles from its most southern border was widely seen as a warning to Vietnam, which earlier this week conducted its own live-fire drills near the Spratly Islands. Several countries claim sovereignty over this string of uninhabited volcanic rocks but rendered attractive by surrounding waters that are fertile fishing grounds and may hold significant reserves of oil and natural gas.
Vietnam, the Philippines, Malaysia and Brunei all claim jurisdiction over some of the territory, as well as over another island chain, the Paracels. But China contends its sovereignty over the archipelagos dates from ancient national maps that show the islands to be an integral part of its territory.
On Friday, state television showed footage of Chinese patrol boats firing repeated rounds at a target on what looked like an uninhabited island, as twin fighter jets streaked in tandem over head. The report said 14 vessels participated in the maneuvers, staging anti-submarine and beach landing drills aimed at "defending atolls and protecting sea lanes."
China has pressed its claim to the outcrops in the South China Sea more assertively in the last two years. In 2010, it declared the sea a "core national interest," the same phrase it uses to signal it will not brook outside interference over its claims to Taiwan and Tibet. Since then, Chinese civilian vessels have increasingly confronted fishing and oil exploration ships from other countries operating in those waters.
The latest spike in tension began late last month when Vietnam accused a Chinese fishing boat, escorted by two patrol boats, of deliberately severing the cable of a seismic survey ship owned by PetroVietnam, the country's national oil and gas company. Relations between the two countries are fraught: they waged a border war in 1979, and have since clashed occasionally at sea over the island chains.
The Vietnamese government is under pressure from its own intensely nationalist media and public opinion to stand up to China. The sea skirmish in May sparked an anti-Chinese outpouring in Vietnam, and the government has permitted rare public demonstrations to allow a mostly youthful crowd to vent their anger.
Social media is also fueling anti-Chinese sentiments, including an online petition to change the name of the South China Sea to the Southeast Asia Sea.
"Vietnam has always been in a bad position to have such a large and powerful neighbor as China, but we are also angry that the Vietnamese government takes such a subservient attitude towards China," said Thuc Vy Huynh, a 27-year-old activist and blogger.
Chinese officials say they are merely protecting their national economic interests.
"We cannot avoid dealing with this issue. The Vietnamese are collecting gas and encroaching on our territory," said Xu Guangyu, a retired Chinese military officer and analyst with the China Arms Control and Disarmament Association.
China has also dispatched its largest civilian vessel to transit through the region, sending the 3,000-ton, helicopter-equipped Haixun to dock in Singapore. And an unidentified Oceanic Administration official was quoted in China's state press saying that the civilian maritime surveillance force would be increased to 15,000 from 9,000 personnel by 2020.
With Vietnam and the Philippines issuing sharp warnings against further Chinese encroachment on their commercial venture, observers say the confrontation has the potential to lead to a clash.
"The highly charged situation in which vessels with paramilitary capabilities ignore each other's signals and engage in provocative actions, could easily devolve into a shooting incident," said Stephanie Kleine-Ahlbrandt of the Beijing office of International Crisis Group. "If bullets fly, we could really see things escalate."