[TOKYO] Some 230 Chinese fishing vessels and six coast guard ships, including three apparently carrying weapons, sailed into waters close to disputed East China Sea islands on Saturday, Japan's foreign ministry said.
The two countries are locked in a long-running dispute over uninhabited islets in the East China Sea known as the Senkaku in Japan and the Diaoyu in China. However, it is rare for so many Chinese fishing vessels to be spotted in the area.
After catching sight of the coastguard ships in the contiguous waters at 8:05 am (2305 GMT, Friday), the Japanese foreign ministry's Asian and Oceanian Affairs Bureau lodged a strong protest with the Chinese embassy in Tokyo, it said.
The foreign ministry, which also submitted a protest its embassy in Beijing, demanded the vessels leave the disputed waters immediately and "never enter Japan's territorial waters", the ministry said in a statement.
"Japan can never accept activities by (Chinese) official vessels near the Senkaku islands, because it will unilaterally escalate the situation and raise tensions in the area," it said.
Saturday's protest came a day after Japanese vice foreign minister Shinsuke Sugiyama summoned Cheng Yonghua, Beijing's ambassador to Tokyo, to protest over intrusions into its territorial waters by Chinese coast guard and fishing vessels on Friday afternoon.
Tensions over the islands have seriously harmed bilateral relations.
The two sides have gradually taken steps to ease tensions through dialogue but the fundamental divide over the islands remains unresolved and tensions occasionally flare up.
Japan also lodged a protest in June after it said a Chinese navy frigate sailed close to territorial waters near the islands for the first time.