China's maritime authority said Friday it will boost surveillance in the East China Sea, and stop Japan's illegal survey activities in accordance with the law to safeguard the country's sea rights.

The remarks made, by an official with the East China Sea branch of the State Oceanic Administration (SOA), came after two vessels of the Japan Coast Guard were discovered conducting survey activities in China's territorial waters in the East China Sea.

Japan's move has severely infringed upon China's sovereignty, and runs contrary to the United Nations Convention on the Law of the Sea and relevant Chinese laws, the official said.

China's position on the East China Sea issue is clear and consistent. It has zero tolerance for Japan's unilateral survey action without permission of the Chinese government.

Japan must halt such activities, otherwise it will bear full responsibility for the consequences, the official said.

Last month, Chinese patrols spotted two Japanese ships, the Takuyo and the Shoyo, carrying out survey activities in China's waters in the East China Sea. The vessels left after receiving a warning from the Chinese side, according to the SOA and China Marine Surveillance.

Chinese Ministry of Foreign Affairs later voiced opposition to Japan's unilateral surveying in disputed waters in the East China Sea.