By Kevin Lim
SINGAPORE (Reuters) - Singapore expressed concern on Monday over China's plan to board and search ships sailing in what it considers its territory in the South China Sea, as tension grows over Beijing's sovereignty claims in busy Southeast Asian waters.
"Singapore is concerned about this recent turn of events," the Ministry of Foreign Affairs said in response to a recent Chinese media report on new rules that will allow police in the southern Chinese province of Hainan to board and seize control of foreign ships which "illegally enter" its waters from January 1.
Wealthy Singapore, home to the world's second-busiest container port, is the second Southeast Asian country to publicly express concern over the new rules after the Philippines on Saturday condemned the Chinese plan as illegal.
The issue divided Southeast Asian leaders at a summit last month in Phnom Penh, where host Cambodia, a staunch China ally, sought to limit discussion on the mineral-rich sea, where China's claims overlap in places with those of four Southeast Asian countries and of Taiwan.
Tension over the South China Sea, home to a third of the world's shipping activity, is entering a new and more contentious chapter, as claimant nations build up their navies and alliances with other nations, particularly with the United States.
"We urge all parties to the territorial disputes in the South China Sea to refrain from provocative behavior," the Singapore government said in a statement.
"It is important for all parties to respect the accepted principles of international law ... and refrain from taking actions that could escalate tensions."
China's sovereignty claims over the stretch of water off its south coast and to the east of mainland Southeast Asia set it directly against U.S. allies Vietnam and the Philippines, while Brunei, Taiwan and Malaysia also lay claim to parts.
The tensions illustrate the difficulty of forging a Southeast Asian consensus over how to deal with an increasingly assertive China.
Estimates for proven and undiscovered oil reserves in the South China Sea range as high as 213 billion barrels of oil, the U.S. Energy Information Administration said in a 2008 report. That would surpass every country's proven oil reserves except Saudi Arabia and Venezuela, according to the BP Statistical Review.
Surin Pitsuwan, secretary-general of the 10-member Association of Southeast Asian Nations, said on Friday the Chinese plan was a "very serious turn of events".
(Writing by Jason Szep; Editing by Robert Birsel)