Chinese government ships enter Japan's territorial waters off Senkaku Islands

The Japan Coast Guard says four Chinese government ships entered Japanese territorial waters near the Senkaku Islands on Friday.

Coast guard officials say the vessels began entering the waters from around 10:30 a.m. and navigated there for about 1 hour and 40 minutes.

They say the vessels later left the territorial waters and were in the contiguous zone just outside Japan's territorial waters near Uotsuri Island as of 12:30 p.m. The coast guard is warning them not to reenter territorial waters.

This is the 23rd time this year and the first since August 23 that Chinese government ships have been spotted in Japan's territorial waters around the Senkaku Islands.

Chief Cabinet Secretary Matsuno Hirokazu told reporters that the Chinese ships left the territorial waters after the coast guard issued repeated demands to depart and enforced route restrictions.

He said the vessels' activities violates international law, and added that the government has lodged a protest through a diplomatic channel.

Calling the intrusion deeply regrettable and unacceptable, Matsuno said the government will continue monitoring the situation around the islands and respond to China calmly and resolutely.

Japan controls the islands. China and Taiwan claim them. The Japanese government maintains the islands are an inherent part of Japan's territory, in terms of history and international law. It says there is no issue of sovereignty to be resolved over them.