YONAGUNI (Japan) • Japan has switched on a radar station in the East China Sea, giving it a permanent intelligence-gathering post close to Taiwan and a group of islands claimed by both Japan and China, drawing an angry response from Beijing.

The new Self-Defence Forces base on the island of Yonaguni is at the western end of a string of Japanese islands in the East China Sea, 150km south of the disputed islands known as Senkaku in Japan and Diaoyu in China. It is 100km east of Taiwan.

China has raised concerns among its neighbours with its assertive claim to most of the South China Sea, where the Philippines, Vietnam, Malaysia, Taiwan and Brunei have overlapping claims.

"Until yesterday, there was no coastal observation unit west of the main Okinawa Island. It was a vacuum we needed to fill," Lieutenant-Colonel Daigo Shiomitsu of Japan's Ground Self-Defence Force, who commands the new base, said yesterday. "It means we can keep watch on territory surrounding Japan and respond to all situations."

Construction of some buildings is still unfinished. The 30 sq km island is home to 1,500 people, most of whom raise cattle and grow sugar cane. The Self-Defence Forces contingent and their family members will increase the population by a fifth.

China's Defence Ministry, in a statement on the radar station, said the international community needed to be on high alert to Japan's military expansion. "The Diaoyu Islands are China's inherent territory. We are resolutely opposed to any provocative behaviour by Japan aimed at Chinese territory. The activities of Chinese ships and aircraft in the waters and airspace are completely appropriate and legal," it said.

The listening post fits into a wider military build-up along the island chain, which stretches 1,400km from the Japanese mainland. Policymakers said last year it was part of a strategy to keep China at bay in the western Pacific as Beijing gains control of the South China Sea.

Over the next five years, Japan will increase its Self-Defence Forces in the East China Sea by about a fifth to almost 10,000 personnel, including missile batteries.

Separately, Japan has conveyed its concern to Moscow over possible Russian plans to build a naval base on a western Pacific island chain, the Kuril Islands, parts of which are claimed by Tokyo.

REUTERS