China's military is building large-scale facilities on islands near the Senkaku Islands, according to several Chinese sources.

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.