MELISSA BLOCK, HOST:
It is a massive dredge-and-fill operation. China's building islands on top of reefs in the contested South China Sea. And now the talk between China and the U.S. is becoming more blunt. Today, President Obama called China's efforts aggressive and unproductive.
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BARACK OBAMA: And it may be that some of their claims are legitimate. But they shouldn't just try to establish that based on throwing elbows and pushing people out of the way. If in fact their claims are legitimate, people will recognize it.
BLOCK: NPR's Anthony Kuhn reports from Beijing. The U.S. and China show no signs of compromising. But for now, neither side wants to escalate the dispute either.
ANTHONY KUHN, BYLINE: Over the weekend, U.S. Defense Secretary Ash Carter visited Vietnam's navy headquarters in the city of Haiphong. Twenty years after the two sides established diplomatic ties, the U.S. still won't sell some weapons to Vietnam because of concerns about Hanoi's human rights record. But the two appear to be making common cause in the South China Sea. Carter inspected a Vietnamese Coast Guard ship which had been rammed by a Chinese vessel in disputed waters last year. He said the U.S. and Vietnam need to step up cooperation.
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ASH CARTER: The United States is going to provide $18 million to the Vietnamese Coast Guard, with whom I visited today, to purchase some American patrol vessels.
KUHN: At a security forum in Singapore over the weekend, Carter called on China, Vietnam and all countries involved in the dispute to stop building on and militarizing the tiny reefs, but he singled out China.
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CARTER: China has reclaimed over 2000 acres, more than all other claimants combined and more than in the entire history of the region. And China did so in only the last 18 months.
KUHN: Carter didn't say exactly how the U.S. will respond to China's actions. He said the U.S. military would continue to operate in international waters and airspace near Chinese territory despite Beijing's objections. And he said it would continue to deploy its best troops and weapons to Asia. China's delegation at the forum vigorously rebutted Carter's remarks. Admiral Sun Jianguo said through an interpreter that China is contributing to regional peace partly by not sticking its claims more forcefully than it has.
ADMIRAL SUN JIANGUO: (Through interpreter) In spite of the sufficient historical and legal evidence and its indisputable claims of rights and interests, China has exercised enormous restraint.
KUHN: Sun would not rule out the possibility that China may, in future, declare an air defense identification zone over the South China Sea as they did over the East China Sea in 2013. In theory, such a zone could require foreign aircraft to obey Chinese military orders. But Ye Qiang, a researcher with the National Institute for South China Sea Studies in Beijing, says even if Beijing does declare such a zone, it would not affect freedom of navigation over these waters.
YE QIANG: (Speaking Mandarin).
KUHN: "Even if foreign military aircraft entered the zone, China would not forcibly drive them out," he says, "and it certainly would not shoot them down." China will not act in self-defense unless the planes enter its territorial airspace. It's not at all clear that China could enforce such a zone. Last month, China's navy did try to order a U.S. spy plane away from a disputed reef. It repeated that order eight times, but the U.S. plane just ignored it. Anthony Kuhn, NPR News, Beijing. Transcript provided by NPR, Copyright NPR.