Chinese ships enter disputed waters: Japan coast guard

Chinese marine surveillance ship Haijian No. 51 (centre) sails near Japan Coast Guard vessels (right and left) and a Japanese fishing boat (front 2nd left) as Uotsuri island, one of the disputed islands, called Senkaku in Japan and Diaoyu in China, i
Chinese marine surveillance ship Haijian No. 51 (centre) sails near Japan Coast Guard vessels (right and left) and a Japanese fishing boat (front 2nd left) as Uotsuri island, one of the disputed islands, called Senkaku in Japan and Diaoyu in China, in background, in the East China Sea on July 1, 2013. -- FILE PHOTO: REUTERS/KYODO 

TOKYO (AFP) - Three Chinese coast guard ships sailed into disputed waters in the East China Sea on Friday as Beijing maintained its defiant stance after United States President Barack Obama backed Tokyo in the row.

The Japanese coast guard said the Chinese vessels entered the 12-nautical-mile band of territorial waters around one of the Senkaku Islands, which China also claims and calls the Diaoyus, shortly before noon.

It was the third-such incursion since US President Barack Obama vigorously reasserted on April 24 that Washington would defend Japan under a bilateral military treaty if China initiated an attack in the tense dispute.

China has already dismissed Mr Obama's position, saying that the islands are "China's inherent territory".

Chinese vessels and aircraft regularly approach the East China Sea archipelago - thought to harbour natural resources - after Japan nationalised some of the islands in September 2012, setting off the latest spate of incidents in a long-running territorial dispute.

Relations between Tokyo and Beijing have fallen to their lowest point for years.