Three Chinese coast guard vessels on Wednesday intruded into Japanese waters around the Senkaku Islands for the first time since the organization was transferred to the command of the Asian power's armed police, prompting the Japanese government to lodge a protest.

The Japan Coast Guard said the vessels stayed in the country's territorial waters for about one and a half hours from around 10:20 a.m. before exiting to the so-called contiguous zone.

At a press conference in Tokyo, Chief Cabinet Secretary Yoshihide Suga said the uninhabited islands in the East China Sea are part of "Japan's inherent territory in terms of history and international law" and the intrusion was "extremely deplorable and unacceptable."

Kenji Kanasugi, director general of the Foreign Ministry's Asian and Oceanian Affairs Bureau, conveyed a protest over the phone to the Chinese Embassy in Tokyo, according to a ministry source.

On Sunday, the Chinese coast guard was placed under the command of the armed police, which is controlled by the country's top military body, the Central Military Commission, led by President Xi Jinping.

Chinese vessels last entered Japanese waters around the islands on June 25. The Japanese-controlled islands are claimed by China and Taiwan, which call them Diaoyu and Tiaoyutai, respectively.

In a message posted on Weibo, China's equivalent of Twitter, the Chinese coast guard also acknowledged that the vessels sailed near the islets.

The Japan Coast Guard said it continued to monitor the Chinese ships, even after they left to the zone just outside Japanese waters, adding one of the vessels was equipped with what appeared to be a cannon.

(A Japan Coast Guard ship sailing parallel to a Chinese vessel in Japanese waters near Senkakus)
[File photo]