(Adds Japanese comments, Taiwan-Japan talks)
By Lucy Hornby
BEIJING, Feb 28 Japan's Foreign Minister Hirofumi Nakasone flew into a diplomatic storm on Saturday, arriving in Beijing one day after China made stern representations over official remarks about disputed islands in the East China Sea.
Japanese Prime Minister Taro Aso had said in parliament on Thursday that the uninhabited islands -- claimed by Japan as the Senkaku and by China as the Diaoyu -- were Japanese territory and thus covered by the Japan-U.S. security alliance, Japan's Kyodo news agency has reported.
Nakasone, visiting China for the first time since becoming foreign minister last September, echoed on Friday comments by a U.S. State Department official that the alliance was applicable to the islands, Xinhua news agency said.
"We have lodged stern representations to Japan again and required the United States to clarify reports on the issue," Chinese Foreign Ministry spokesman Ma Zhaoxu said in a statement on the ministry website (www.mfa.gov.cn).
"Any words and deeds that bring the Diaoyu islands into the scope of the Japan-U.S. Mutual Cooperation and Security Treaty are absolutely unacceptable to the Chinese people," Ma said.
Japanese Foreign Ministry media secretary Kazuo Kodama acknowledged that the islands were a "sensitive issue," but said that Nakasone hoped to begin negotiations with the Chinese to turn a political agreement last summer over resource development in the East China Sea into a more formal international treaty.
"This is a sensitive issue for the people in China, and maybe in Japan, but ... we would like to see progress," Kodama said.
Ma said the Diaoyu and adjacent islets have been Chinese territory since ancient times and China held "indisputable" sovereignty over them.
Ma also urged the two countries to realise the sensitivity of the issue and proceed with discretion to avoid damage to the interests of China-Japan and China-U.S. relations and regional stability.
It was the second time in three months Sino-Japanese ties have been strained by the long-running dispute over the islands, which may lie near potential oil and gas reserves.
On June 18, the two countries agreed to joint development of the northern waters of the East China Sea and on Japanese participation in an oil field, known as Chunxiao or Shirakaba, which the Chinese side has already begun developing.
During his two-day visit Nakasone is to meet his Chinese counterpart Yang Jiechi later on Saturday and Chinese Premier Wen Jiabao on Sunday.
North Korea, cooperation in the face of the economic crisis, climate change and strengthened extradition treaties are all on the agenda, Kodama said. The Japanese side will also urge faster resolution of a Chinese investigation into tainted dumplings.
Taiwan and Japan agreed during talks in Taipei on Thursday and Friday to share any urgent information about fishing boat activity and to let a pair of non-governmental agencies hash out any disputes, Taiwan's foreign ministry said.
In June a Taiwan fishing boat collided with a Japanese coastguard vessel and sank off the Japan-controlled islands, also claimed by Taiwan as Tiaoyutai. Japan held the Taiwanese captain for investigation.
After the incident, Taiwan's normally pro-Japan government lashed out at Tokyo, demanding an apology. (Additional reporting by Ralph Jennings in TAIPEI and Benjamin Kang Lim in BEIJING; Editing by Paul Tait)