Beijing has lodged a solemn representation to Tokyo over local Japanese lawmakers' activities in the waters off the Diaoyu Islands, the Foreign Ministry said on Tuesday.

Media reports said eight Tokyo Metropolitan Assembly members departed on Monday night to conduct a so-called survey in the waters off the islands in the East China Sea.

The representation was the second in a month. Beijing lodged an official protest earlier in the month over a fishing campaign held by a group of conservative Japanese politicians and political activists on June 10 in waters near the islands.

"China has lodged solemn representations with Japan, demanding that Japan stop creating new disturbances and safeguard the overall interest of China-Japan relations with concrete actions," Foreign Ministry spokesman Hong Lei said at a daily news conference.

Hong reiterated that the Diaoyu Islands and its affiliated islands have been China's inherent territory since ancient times, and China has indisputable sovereignty over them. "Any unilateral move taken by Japan over the Diaoyu Islands is illegal and invalid," he said.

This year marks the 40th anniversary of the normalization of diplomatic relations between China and Japan, yet a series of remarks and activities by some Japanese politicians has added to the tension over the islands.

In April, Tokyo Governor Shintaro Ishihara said his city prefecture was negotiating with the "owner" of the islands in the hope of "buying them by the end of this year".

Ishihara said at a news conference on Friday that the islands purchase plan "should not be given up halfway". He even indicated that he intended to win the following re-election to finish his plan, Kyodo News Agency reported.

Japanese Prime Minister Yoshihiko Noda visited the 11th regional headquarters of the Japan Coast Guard in Naha City, Japan, on Saturday to encourage officers who patrol the waters surrounding the islands, Japan's Jiji News Agency said.

Yet during a meeting with Premier Wen Jiabao in mid-May in Beijing, Noda agreed that the islands issue should not affect China-Japan ties, and Wen called for Japan's due respect for China's core interests and major concerns in the context of the ongoing moves toward "buying" the islands.

Vice-Premier Li Keqiang reiterated Beijing's stance on the islands during a talk with former Japanese prime minister Yukio Hatoyama in late May in Beijing.

However, local officials from Tokyo and Ishigaki increased their communication on the issue after Ishigaki Mayor Yoshitaka Nakayama proposed a joint purchase of the islands to the Tokyo prefectural government in early May.

During a meeting on Tuesday with a visiting delegation of senior Tokyo prefectural government officials, the Ishigaki side proposed to dispatch personnel to "join the survey ship mission by the Tokyo prefectural government" in the future, Kyodo reported.

zhangyunbi@chinadaily.com.cn

(China Daily 06/27/2012 page12)