The United States on Tuesday warned against any attempt to "divide and conquer" in the tense South China Sea, and voiced hope that Beijing and Southeast Asian nations would reach an accord this year.

Several Southeast Asian nations have accused China of aggravating friction in the South China Sea, but foreign ministers from the 10-nation ASEAN bloc failed at a meeting last month to reach an agreement on the way forward.

China, which claims sovereignty over virtually the entire sea, has favored individual talks with each nation over disputes.

State Department spokeswoman Victoria Nuland reiterated that the United States preferred a deal that included every country with claims in the South China Sea.

"An effort to divide and conquer and end up with a competitive situation among the different claimants is not going to get where we need to go," Nuland told reporters, without explicitly naming China.

"What we're most concerned about at the moment is that tensions are going up among the stakeholders. So we want to see a commitment to a deal that meets the needs of all," she said.

The United States has been pushing for a code of conduct in the South China Sea that would set up formal channels to resolve friction and prevent miscalculations in the waters through which half of the world's cargo passes.

But ASEAN, the Association of Southeast Asian Nations, is divided. The Philippines and Vietnam are strongly critical of China but Cambodia, the host of the July talks of foreign ministers, has close relations with Beijing.

Attending the talks in Phnom Penh, Secretary of State Hillary Clinton encouraged China and ASEAN "to work together on a code of conduct and for all of them to commit as soon as they can -- to do that work and ideally to do it this year," Nuland said Tuesday.

Nuland was reacting to a commentary by China's state-run news agency, Xinhua, which denied charges that Beijing was sowing division in Southeast Asia and hit back hard at "some Western countries."

"What in fact is blocking unity within ASEAN and between its allies is the meddling of some Western countries that are betting on a divided Asia. They loathe to see Asia's incredible economic vitality while their economies are waning, as is their influence in the world," Xinhua said.

President Barack Obama has vowed a renewed US focus on Asia. The United States has sought to reassure US-friendly Asian nations through its military presence and plans to shift the bulk of its naval fleet to Asia by 2020.

Clinton, on a visit to Vietnam in 2010, declared that the United States had a national interest in freedom of navigation in the South China Sea.

On August 3, the State Department again voiced concern as it accused China of risking an escalation of tensions by establishing the tiny city of Sansha and a military garrison in the disputed Paracel chain.

In addition to China, the Philippines, Vietnam, Malaysia, Brunei and Taiwan have sometimes overlapping claims to the South China Sea.

China's Foreign Minister Yang Jiechi recently visited Brunei, Indonesia and Malaysia. In Jakarta, he said that Beijing was willing to work to maintain peace and stability in the South China Sea.