Southeast Asian officials meeting this week in Cambodia are pushing for a long-sought solution for resolving territorial disputes in the South China Sea, an area claimed in part by six nations.

ASEAN foreign ministers approved a set of guidelines last year that they hoped would lead to a code of conduct. But with no binding deal, disputes have continued.

Last month, Vietnam protested China's decision to post bids on offshore oil blocks in the South China Sea, which is home to vast fishing grounds and potential oil and gas deposits. Vietnam said the areas were entirely within its exclusive economic zone and continental shelf, and its National Assembly passed a law stating its claims in the area.

China strongly criticized the law, saying it was illegal.

Taiwan, the Philippines, Brunei and Malaysia also claim territory in the sea.

At the opening of the annual ASEAN foreign ministers meeting Monday, Cambodian Prime Minister Hun Sen stressed the need for an agreement.

“We should put emphasis on the implementation of the Declaration of Conduct, including the eventual conclusion of the Code of Conduct in the South China Sea. In addition, we need to ensure the official launching of the ASEAN Institute of Peace and Reconciliation and the conclusion of the ASEAN Human Rights Declaration at the (upcoming) 21st ASEAN Summit in order to promote peace and reconciliation and human rights protection in the region.”

ASEAN and China signed a Declaration of Conduct in 2002 that calls for free navigation in the South China Sea, resolving disputes peacefully, and respect for international agreements, including the U.N. Convention on the Law of the Sea.

U.S. Secretary of State Hillary Clinton will take part in the ASEAN talks during a two-week Asian tour. She told reporters Sunday in Tokyo that every nation has an interest in the freedom of navigation and “unimpeded, lawful commerce in the South China Sea.”

“Therefore we believe the nations of the Asia Pacific region should work collaboratively and diplomatically to resolve their disputes without coercion, without intimidation, without threats, and without conflict. We want to see all parties with claims – whether they are land or maritime claims – pursue them in accordance with international law, including as reflected in the Law of the Sea Convention.”

The European Union and 161 countries have ratified the U.N. treaty that went into effect in 1994. The pact governs how nations may use the world's oceans and the resources they contain.

The United States is the only industrialized nation that has not signed the treaty.

Clinton and top U.S. military leaders urged the Senate to approve joining the treaty during hearings in May, but former top officials, including ex-defense chief Donald Rumsfeld said they opposed the move. A vote is not expected before the November presidential election.