Japan continued to challenge China's sovereignty over the Diaoyu Islands at the weekend as a team organized by the government of Tokyo conducted a so-called survey in waters off the islands on Sunday.
The survey, reportedly in preparation for Tokyo's purchase of the islands, is illegal, according to Chinese experts. They added that if Japan sticks to its plan to purchase Diaoyu, it will further exacerbate disputes with China.
The group spent nine hours surveying the temperature and quality of the seawater as well as the shoreline and other geographical features of the Diaoyu Islands, the Xinhua News Agency said.
Besides surveying the living conditions of some seabirds and goats, the team also measured the depth of surrounding waters to ascertain whether the area was fit to build port facilities to shelter fishing boats, according to NHK World.
The team was made up of 25 members, including officials from Tokyo and Ishigaki governments, real estate appraisers, maritime policy experts and one university professor, according to Xinhua.
The group's voyage seriously infringed upon China's sovereignty, Liu Jiangyong, a professor of international studies at Tsinghua University, told the Global Times Sunday.
"Although the Japanese central government refused to give this team permission to land, it should not let this voyage around the Diaoyu Islands go unchecked," said Liu.
Gui Yongtao, associate professor with the School of International Studies at Peking University, told China Central Television that the Japanese side is sending out "a fairly confusing message" on the Diaoyu Islands issue. He added it would be difficult for China to accept Japan's request of reconciliation since Japan was sticking to its plan to purchase the islands.
Japanese Vice Foreign Minister Tsuyoshi Yamaguchi Friday handed the Chinese government a letter written by Japanese Prime Minister Yoshihiko Noda to Chinese President Hu Jintao, in a bid to improve ties.
Tokyo plans to conduct another survey on Diaoyu in October, in which Tokyo governor Shintaro Ishihara will take part, Xinhua reported.
Sino-Japanese relations have become tense once again since some Chinese activists landed on the Diaoyu Islands and were arrested by the Japanese coast guard in August.