NAHA (Kyodo) -- A Chinese fisheries patrol vessel sailed inside Japanese territorial waters near the disputed Senkaku Islands in the East China Sea for the second consecutive day on Sunday, the Japan Coast Guard said.

The Chinese vessel sailed in the waters for around 15 minutes from around 8:20 a.m., following Saturday's intrusion, and moved to the contiguous zone just outside the waters.

Shinsuke Sugiyama, director general of the Japanese Foreign Ministry's Asian and Oceanian Affairs Bureau, contacted Han Zhiqiang, Chinese minister-counselor to Japan, by phone to lodge a protest over the incident.

Han said the Chinese side could not accept the protest but would convey the Japanese side's message to Beijing.

It marks the 30th entry into Japanese waters by a Chinese government ship or ships since Tokyo purchased a major part of the Senkakus, called Diaoyu in China, last September.

Responding to the coast guard's warning not to enter Japanese waters, the vessel replied by radio that the Senkakus are inherently Chinese territory, according to the 11th Regional Coast Guard Headquarters in Naha, Okinawa Prefecture.