WASHINGTON • While attention in Asia has been distracted by the North Korean nuclear crisis in the past year, China has continued to install facilities that can be used for military purposes on its man-made islands in the South China Sea, a US think-tank said.

Chinese activity has involved work on facilities covering 29ha of the Spratly and Paracel islands, territory also claimed by several other Asian nations, according to the Asia Maritime Transparency Initiative of Washington's Centre for Strategic and International Studies. The report cited satellite images.

The United States and its allies oppose China's building of artificial islands in the South China Sea and their militarisation, given concerns that Beijing plans to use them to deny access to strategic routes.

The report said that in the past several months China had constructed what appeared to be a new high-frequency radar array at the northern end of Fiery Cross Reef in the Spratlys.

Subi Reef had seen tunnels completed that were likely for ammunition storage and another radar antenna array and radar domes, the report added.

Construction on Mischief Reef included underground storage for ammunition and hangars, missile shelters and radar arrays.

Smaller-scale work had continued in the Paracel Islands, including a new helipad and wind turbines on Tree Island and two large radar towers on Triton Island.

It said the latter were especially important as waters around Triton had been the scene of recent incidents between China and Vietnam and multiple US freedom-of-navigation operations, which the US navy has used to assert what it sees as its right to free passage in international waters.

China yesterday said it was within its rights to build facilities in the South China Sea.

"It's completely normal for China to conduct peaceful construction and build essential defence equipment on its own sovereign territory," Foreign Ministry spokesman Lu Kang told a regular press briefing in response to a question about the report.

REUTERS