Eight Chinese maritime surveillance vessels entered Japanese territorial waters Tuesday around the Senkaku Islands in the East China Sea, the Japan Coast Guard said.

China's State Oceanic Administration said the vessels were there to monitor the activity of a flotilla of boats reportedly carrying members of a Japanese nationalist group. China regards the area as its territorial waters.

This is the most Chinese ships to enter Japanese waters near the Senkakus since the central government purchased three of them from their Saitama owner last September and effectively nationalized the chain, according to the 11th Regional Coast Guard Headquarters in Naha, Okinawa Prefecture.