Japan says an armed Chinese coast guard vessel has entered what Tokyo considers its territorial waters near the disputed East China Sea islands for the second time in less than a week.
According to a statement by the Japanese coast guard, the ship approached the waters north of Kuba Island at around 9:30 a.m. (0030 GMT) Saturday and stayed there for about an hour.
The ship, which appeared to be armed with several cannons, was accompanied by two other coast guard vessels without such equipment.
Kuba is among the East China Sea islands, whose sovereignty is disputed by Tokyo and Beijing.
Relations between China and Japan have soured in the past years over a territorial row on the uninhabited yet strategically-important island group in the East China Sea. Tensions grew after Tokyo nationalized part of the resource-rich islands in 2012.
China maintains that the islands are inherent parts of its territory and that it has indisputable sovereignty over them, while the Japanese government regards the islands as a part of its Ishigaki Island in Okinawa Prefecture.
The islands have been under Japanese administrative control since the reversion of Okinawa to Japan from US administrative rule in 1972.
Beijing also claims the South China Sea almost in its entirety and is involved in a series of disputes with several neighboring countries over the issue.
Last month, China called on other countries in the region to engage in direct talks over any disputed territory.