Construction is underway in the Nanji Islands in Zhejiang province, about 300 km to the northwest of the Japanese-controlled Senkakus, which China calls the Diaoyu.
The base is expected to enhance China’s readiness to respond to potential military crises in the area as well as to strengthen surveillance over the air defense identification zone it declared over part of the East China Sea in November 2013, the sources said Sunday.
The sources said that several large radar installations have been built at high points on the main Nanji Island.
Several landing strips have been paved, likely for use by aircraft based on warships or patrol vessels, and more landing strips are set to be built on an island adjacent to Nanji Island from around next year, they said.
As the archipelago of 52 islands and islets is located about 100 km closer to the Senkakus than Okinawa’s main island, home to bases of the Self-Defense Forces and the U.S. military, the new base is likely to shake up Japan-U.S. security strategies relating to defense of the Senkaku Islands.
Li Jie, a senior researcher from the Chinese Naval Research Institute, said the People’s Liberation Army already has a military presence — including a radar system — in the islands.
“It’s a strategically important location because of its proximity to the Diaoyu Islands; it can provide support to the East China Sea air defense zone; and it’s a major naval point on the Chinese coastal defense lines,” he said.
“It’s unarguable that China wants to enhance the existing military presence there,” he said.
Chief Cabinet Secretary Yoshihide Suga told reporters in Tokyo on Monday that the government is analyzing the developments.
“China has rapidly increased its activities in surrounding waters and airspace, and we will continue to watch these movements,” he said.
Xu Guangyu, a retired major general and senior adviser at the Beijing-based research group China Arms Control and Disarmament Association, said it is “absolutely normal” for the Chinese military to maintain or upgrade facilities on the Nanji Islands.
“China has military bases in several strategically important coastal islands, and the Nanji (chain) is one of them. The Japanese media is only singling out the Nanji and making a big fuss: This can be misleading.”
In April, Japan began construction of a surveillance center on the remote island of Yonaguni to monitor activity around the disputed islands.