China on Monday justified the entry of its coast guard vessels into Japan's territorial waters near the Tokyo-controlled, Beijing-claimed Senkaku Islands in the East China Sea, saying they are the country's "inherent territory."

Last Monday, China put into effect the controversial legislation that allows its coast guard to use weapons against foreign ships that it sees as illegally entering its waters, sparking fears that Japanese vessels navigating around the Senkakus would be targeted.

Beijing's patrol and legal enforcement activities in the waters near the islets are "legitimate measures taken by China to safeguard sovereignty in accordance with law," Foreign Ministry spokesman Wang Wenbin told reporters.

Chinese coast guard ships on Sunday entered Japan's territorial waters around the islands for the second day in a row. Wang did not elaborate what kind of activities the vessels were engaged in.

Tokyo lodged a protest with Beijing through multiple diplomatic channels on Saturday, after Chinese coast guard ships intruded into Japan's territorial waters near the Senkakus, called Diaoyu in China, for the first time since the new law took effect.

Sino-Japanese relations have been often frayed by the territorial issue.

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