Stay out of talks over the South China Sea: Beijing tells Washington

Ambassador Cui Tiankai said the U.S. has no territorial claim in those waters and should let countries in the region manage their disputes in a "friendly and effective way." Beijing's island-building in the South China Sea has drawn criticism from Washington which says it has a national interest in freedom of navigation in sea lanes critical for world trade. Secretary of State Rex Tillerson this month said China's "provocative actions" challenge international law and norms.

Efforts to forge a legally binding code of conduct between China and the diverse members of the 10-nation Association of Southeast Asian Nations, or ASEAN, have long been stymied by Beijing's reluctance to negotiate with nations as a bloc and differences within ASEAN itself. Singapore's prime minister last week said the negotiations were likely to take years.

China has quietly undertaken more construction and reclamation in the South China Sea, recent satellite images show, and is likely to more powerfully reassert its claims over the waterway soon, regional diplomats and military officers say.

With global attention focused on North Korea and Beijing engrossed in its Party Congress, tensions in the South China Sea have slipped from the headlines in recent months.

But with none of the underlying disputes resolved and new images reviewed by Reuters showing China continuing to develop facilities on North and Tree islands in the contested Paracel islands, experts say the vital trade route remains a global flashpoint.

Some expect China to land its first deployments of jet fighters onto its runways in the Spratly islands in coming months, while regional military officers say it is already using the new facilities to expand naval and coast guard deployments deep into Southeast Asia.

"They've built these extensive facilities and both Chinese civilian and PLA experts have always made it clear that when the strategic time is right, they're going to start using them more fully," said Bonnie Glaser, a China security expert at Washington's Center for Strategic and International Studies.