Three Chinese ships entered disputed waters off Tokyo-controlled islands in the East China Sea on Sunday, the Japanese coastguard said, the first such incident since Beijing announced an air defence zone in the area last month.

The vessels entered the 12-nautical-mile territorial waters at about 9:00 am (0000 GMT) off one of the Senkaku islands, which China also claims and calls the Diaoyus, the Japan Coast Guard said. They left the area shortly after noon.

It was the first time that Chinese coastguard ships had been spotted sailing through the waters since Beijing raised regional tensions with its declaration of an Air Defence Identification Zone in November.

Chinese vessels have sailed in and out of contiguous waters around the islands but stayed away from entering territorial waters since November 22, a Japanese coastguard official said.

Japan's conservative Prime Minister Shinzo Abe has vowed no compromise on sovereignty of the islands and stepped up defence spending, believing that China is trying to change the status quo through growing sea incursions.

Chinese state-owned ships and aircraft have approached the Senkakus on and off to demonstrate Beijing's territorial claims, especially after Japan nationalised some of the islands in September last year.

US looks to manage, not end, China air rift
Washington (AFP) Dec 07, 2013 - The United States has strenuously objected to China's new air zone over islands managed by Japan, but experts say its best hope is to contain rather than end tensions.

After Beijing last month declared an Air Defense Identification Zone in the area of the East China Sea, asking foreign planes to identify themselves, the United States defiantly flew through B-52 jets. US allies Japan and South Korea followed suit.

But in Washington, few are holding their breath that China -- where hostility toward Japan runs deep -- will reverse its decision. President Barack Obama's administration has instead put a priority on preventing an escalation.

Vice President Joe Biden met Wednesday for more than five hours with Chinese President Xi Jinping.

He said later of his talks in Beijing: "I was absolutely clear on behalf of my president: We do not recognize the zone. It will have no effect on American operations. Just ask my general -- none, zero."

But the United States has not explicitly called on China to rescind the zone and instead has called on China to set up an emergency hotline with Japan to prevent a mishap between the world's two largest economies.

"The possibility of miscalculation -- mistake -- is real and could have profound consequences for your generation," Biden said Friday at Yonsei University in Seoul.

Japan administers the tiny Senkaku islands, which China calls the Diaoyu and links to Tokyo's imperialist past.

Japan's conservative Prime Minister Shinzo Abe has vowed no compromise on sovereignty and stepped up defense spending, believing that China is trying to change the status quo through growing sea incursions.

Several US-based experts suspected that China had goals beyond its row with Japan. China, which has been ramping up military spending over its past decade of strong economic growth, also has tussled with the Philippines and Vietnam over maritime territories.

"I don't see the Chinese rolling it back. I don't think for domestic political reasons that that would be an easy thing to do to begin with," said Sheila Smith, a senior fellow at the Council on Foreign Relations.

"They clearly have, I think, done it with the intention of pursuing aims that are far beyond the China-Japan island dispute. I think it's a bigger piece of their strategic puzzle. So I think management is where we probably should focus our attention," she said.

A warning for the future

The United States, while insisting it does not take sides on sovereignty disputes, has said that the islands in the East China Sea are under Tokyo's management and hence come under a security treaty in which it is required to defend officially pacifist Japan against attack.

With several nations concerned about China's rise, Obama has declared Asia to be a top priority and shifted naval resources there, although the United States is also reducing military spending -- which is more than four times China's official level -- to tame a debt from wars in Iraq and Afghanistan and a recession.

Zheng Wang, a professor at Seton Hall University, said that the US reaction to the air zone would discourage Chinese policymakers if they consider similar moves elsewhere -- such as in the South China Sea.

"I think there are several indicators suggesting that the response from the outside is beyond Chinese expectations. So if they can learn the lessons, I don't think they will make similar announcements in the near future," he said.

Wang said that the Chinese leadership may not have thoroughly studied the special zone plan and would at least learn to communicate better with other nations on its decisions.

But Wang doubted that China would revise its decision, saying that Beijing likely believes it is being held to a double standard as other nations also have Air Defense Identification Zones.

Yoshihide Soeya, a professor at Keio University in Tokyo and a scholar at the Woodrow Wilson International Center for Scholars in Washington, expected that China may be planning further steps. He warned of risks from overlapping air zones.

He said that a hotline between Japan and China would prove helpful, noting that Japan and South Korea, despite often rocky relations, already have one.

If all three countries had a hotline, "this would be beautiful crisis management," he said.