BEIJING - China on Wednesday expressed dissatisfaction over Japan's unilateral marine research in disputed areas of the East China Sea.

Foreign Ministry spokesman Hong Lei made the remarks at a regular news briefing.

On Tuesday, a Chinese vessel radioed the Japanese Coast Guard ship Takuyo and called on it to stop its activities in disputed areas of the East China Sea.

It is reported that Japan's top government spokesman Osamu Fujimura said Wednesday that the marine research was conducted in the country's exclusive economic zone and Japan has protested China's recent call through the official channels.

"China's stance on the East China Sea is clear and consistent," said Hong.

China has expressed dissatisfaction over Japan's unilateral marine research in disputed areas of the East China Sea regardless of China's opposition, he said.

He said China has requested the Japanese side stop relevant activities and avoid damaging China's right and interests, in a bid to safeguard the stability of the East China Sea and the overall relations between the two countries.