China and Southeast Asian countries have made progress on a South China Sea pact but won't be able to conclude decades of negotiations this year as agreed, three regional diplomats said Wednesday.

China and the Association of Southeast Asian Nations began negotiating the so-called "code of conduct" in 2005 to prevent occasional confrontations in the disputed waters from turning into a major conflict that could threaten Asia's economies.

The accord mainly calls for self-restraint and discourages aggressive acts that could spark clashes in the waterway that is a key global trade route.