Sub crosses the line

A nuclear-powered PLA submarine breached a line drawn by a US-led alliance to containing China's naval power, according to a Japanese report.

The conservative Sankei newspaper said the Han-class boat penetrated what Chinese strategists call the 'first island chain' in February 2009. It escaped detection by Japanese naval patrols and anti-submarine aircraft, as Japan's Self-Defence Forces cut back on operations because of rising oil prices.

The newspaper said a similar submarine also breached Japanese territorial boundaries in 2004, triggering a diplomatic row when Tokyo's demand for an apology was rejected by Beijing.

Chinese strategists say some countries have formed an alliance to stop the Chinese military breaking through the chain, which stretches from Japan along the islands of Okinawa down to the Philippines and Indonesia.

The waters are potentially rich in oil and natural gas, and China has disputed claims to numerous islands and the resources that control of them would bring.