BALI, Indonesia - Premier Wen Jiabao on Saturday faced foreign challenges on China's stance on the South China Sea issue candidly, stressing Beijing is willing to work together with Southeast Asian nations for a code of conduct in the waters.

He made the remarks at the East Asia Summit (EAS) at the resort island of Bali. The summit gathered leaders of the 10 members of the Association of Southeast Asian Nations (ASEAN) and their eight partners, including China, India and the United States.

The summit "is not the appropriate place to talk about the South China Sea issue. But since the leaders of some countries have singled us out, it is impolite not to reciprocate," Wen said, in an apparent reference to Washington's call with the Philippines and Vietnam to discuss the dispute at a summit originally designed for regional development discussions.

This is the first time the US is attending he meeting, coming immediately after US President Barack Obama announced a foreign policy pivot to Asia.

Economic developments in East Asia and Southeast Asia since 2002, when China and ASEAN countries signed the Declaration on the Conduct of Parties in the South China Sea, testify to the fact that the freedom of navigation in the area "has not been affected whatsoever" by existing disputes, Wen said. Beijing, he added, has been making efforts to protect marine security in the waters.

The premier said East Asian countries are capable of solving the dispute by themselves.

The EAS should stick to its nature of a strategic forum and "cannot deviate" from its themes of solidarity, development and cooperation, he said.

"The premier's speech showcased China's consistent stance, serves as a warning to big powers outside this region, and sends that message to the international community," said Wu Shicun, president of the National Institute for South China Sea Studies.

China believes in freedom of navigation in the South China Sea and benefits from it as much as other countries in the region and the international community, he said.

Wu said China has shown "significant sincerity" to the region by offering ASEAN another $10 billion in loans on Friday, on top of a pledge of $15 billion in loans in 2009, with a promise to start discussions with relevant parties on a legally binding code of conduct for the South China Sea.

The US has reiterated its interests in ensuring freedom of navigation and the free flow of commerce in the South China Sea, where a third of the world's seaborne commerce is conducted.

Vietnam, the Philippines and Malaysia - all ASEAN members - have pushed competing claims of sovereignty over some islands in the historically Chinese region, while Brunei also holds claims there. Tensions have escalated since summer.

Assistant Foreign Minister Liu Zhenmin on Saturday said Beijing looks forward to cooperating with the US in the Asia-Pacific. But he said China insists that the South China Sea issue should be confined to talks between the parties directly involved through negotiation.

Niu Xinchun, a researcher with the China Institutes Of Contemporary International Relations, said the US is playing a de facto "offshore balancer" role to counter China.

Some claimant countries have used Washington to their own advantages in order to intimidate China, Niu said.

"They should think it over: Will the US engage militarily if clashes break out? Will it be good, really, to bring a third party into the consultation process?"

Calling for a more pro-active role for ASEAN, Mira Permatasari, a lecturer on international relations with the Parahyangan Catholic University in Indonesia, wrote for the Jakarta Post: "The world is fully aware that by having a closer relationship between China and ASEAN's member states through the ASEAN-China Free Trade Agreement, China is confident enough to challenge the incumbent superpower to collect Asian support."

Trade volume between China and ASEAN may surpass $350 billion this year. China is already the regional bloc's top trading partner, while the region ranked third in Beijing's trading list.