A look at some recent key developments in the South China Sea, where China is pitted against smaller neighbors in territorial disputes over islands, coral reefs and lagoons in waters rich in fish and potential gas and oil reserves:
EDITOR'S NOTE: This is a weekly look at the latest key developments in the South China Sea, home to several territorial conflicts that have raised tensions in the region.
CHINA CHEERS WARMING US-VIETNAM TIES
China publicly says it welcomes the Obama administration's decision to lift an arms embargo on Vietnam, although privately, Beijing is likely less than pleased to see warming relations between its southern neighbor and chief regional rival.
Asked about the move, Chinese Foreign Ministry spokeswoman Hua Chunying said that "as a neighboring country, we would be happy to see Vietnam develop normal and friendly cooperative relationships with all other countries, including the United States.
"And we hope those normal and friendly relationships are conducive to regional stability and development," she told reporters at a regularly scheduled news conference.
Such embargoes are "a product of the Cold War, and should not have existed," Hua said. She added that China hopes similar embargos will also be lifted, a possible reference to the continuing weapons embargo imposed by the U.S. and the EU following China's 1989 bloody military crackdown on pro-democracy demonstrations centered on Beijing's Tiananmen Square.
Obama said the embargo's lifting was not based on relations with China, but on a desire to complete what has been a lengthy process of normalizing relations between the United States and Vietnam. He did, however, say that there was mutual concern with respect to maritime issues.
China has looked on warily as the U.S. and Vietnam have steadily strengthened their relationship in recent years, in line with growing Vietnamese concern over aggressive Chinese moves to assert its South China Sea maritime claims. Despite being fraternal Communist neighbors, China and Vietnam fought a bloody border war in 1979, and clashes in 1988 over their conflicting claims in the South China Sea claimed dozens of lives. Those tensions reared again in 2014, when China parked an oil rig off Vietnam's central coast, sparking confrontations at sea and deadly anti-China riots in Vietnam.
CHINA REJECTS US ACCUSATION OF UNSAFE INTERCEPT IN AIR
China last week rejected U.S. claims that its fighter jets maneuvered unsafely when they intercepted an American Navy reconnaissance plane over the South China Sea, and demanded that the U.S. end such missions close to Chinese territory.
The Chinese jets monitored the U.S. plane from an acceptable distance and operated in a safe and professional manner, Foreign Ministry spokesman Hong Lei told journalists at a regularly scheduled news briefing.
"According to the related Chinese authorities, the U.S. allegation is not true," Hong said.
Frequent reconnaissance missions by U.S. Navy vessels' aircraft off the Chinese coast jeopardize China's sea and air safety, Hong said. "We urge the U.S. to immediately stop spying activities and prevent such events from happening again," he said.
The Pentagon said two Chinese J-11 fighters flew within about 15 meters (50 feet) of the U.S. EP-3 Aries aircraft on Tuesday, forcing the U.S. pilot to descend sharply to avoid a collision. It said the U.S. plane was conducting routine operations in international airspace.
It characterized the incident as an unsafe intercept and said it is being reviewed.
The U.S. has sought to prevent such confrontations through frequent communication and the signing of an agreement on handling unexpected encounters at sea and in the air.
Defense Department spokesman Peter Cook on Thursday disputed Chinese officials who rejected U.S. claims that its fighter jets maneuvered unsafely.
"There were two Chinese aircraft that approached and our air crew felt that the approach was not conducted in the safest — a safe and professional manner," Cook said. "That's the concern that we have and that's what's being reviewed at this time."
He said the U.S. is confident that the American crew was flying in international airspace.
State Department spokesman John Kirby said there were plenty of ways for the U.S. and Chinese militaries to communicate.
"The problem isn't, 'Are you talking?' The problem is this kind of behavior, this very unsafe and dangerous behavior in the air which puts people's lives at risk unnecessarily," he told reporters in Washington.
Such incidents may now be on the increase as the U.S. challenges China's claims that its newly created artificial islands in the South China Sea enjoy legal rights to territorial seas and airspace. China says it is entitled to keep watch over such airspace and seas.
China has long been irked by U.S. reconnaissance missions off the Chinese island province of Hainan, which sits at the northern end of the South China Sea and is home to a number of highly sensitive naval and air installations.
In 2001, a collision between a Chinese fighter jet and a U.S. surveillance plane in which the Chinese pilot was killed and the American crew was detained on Hainan led to a crisis in U.S.-China relations.
CHINA ATTRACTS MORE DIPLOMATIC SUPPORT
China last week won the endorsement of landlocked Afghanistan for its stance on the South China Sea dispute, the latest country from outside the region to line up behind China's calls for bilateral talks on the issue.
The Foreign Ministry said Afghan Chief Executive Abdullah Abdullah made the statement in a meeting with Chinese Premier Li Keqiang in Beijing that also touched on security cooperation along their border in China's volatile western region of Xinjiang.
"Our Afghan counterparts expressed their gratitude for China's long-term support over the years, and also said they support China's position on the South China Sea issue and support China's efforts to resolve the South China Sea issue through bilateral channels and through peaceful means such as negotiation and consultation," the deputy director general of the ministry's department of Asian Affairs, Hou Yanqi, told reporters following the talks.
China claims that countries as varied as Russia, Laos, Cambodia and Slovenia have lent their support to China's approach, an attempt by Beijing to counter criticism of its rejection of a case brought before a U.N. tribunal by the Philippines challenging China's territorial claims.