JAKARTA China's plan to board and search ships that illegally enter what Beijing considers its territory in the disputed South China Sea is a very serious turn of events, the head of the Association of Southeast Asian Nations (ASEAN) said on Friday.
"My reaction is (this is) certainly an escalation of the tension that has already been building. And it is a very serious turn of events," ASEAN Secretary-General Surin Pitsuwan told Reuters.
"It is extremely important to exercise restraint and to try to approach this development with a level head and be open to listen to concerns of all parties, all sides," he said.
The South China Sea is Asia's biggest potential military trouble spot with several Asian countries claiming sovereignty over waters believed to be rich in oil and gas.
China claims virtually the entire sea. The Philippines, Taiwan, Vietnam, Brunei and Malaysia claim various parts.
(Reporting by Matthew Bigg; Editing by Raju Gopalakrishnan)