China's Foreign Minister, Yang Jiechi
China will lodge a complaint with Japan after it detained five Chinese activists who landed on disputed islands on Wednesday, China's Xinhua news agency said, as tension between Japan and its neighbours escalated on the anniversary of the end of World War Two.
The landing by the activists on the islands in the East China Sea and their detention by Japan's coastguard came on a day of regional diplomatic jousting, underscoring how history haunts Japan's ties with China and South Korea, reports Reuters.
Earlier, South Korea prompted an official protest from Japan after comments by South Korean President Lee Myung-bak which some saw as going too far by insulting Japanese Emperor Akihito.
And in a move likely to anger Japan's neighbours, two Japanese cabinet ministers paid homage at a controversial Tokyo shrine for the war dead.
Memories of Japan's wartime occupation of much of China and colonization of South Korea run deep despite close economic ties in one of the world's wealthiest regions.
Japan arrested the five members of a group of activists from China, Hong Kong and Macau who landed on the island chain, Japan's coastguard said.
Japan protested to China's ambassador over the landing and Prime Minister Yoshihiko Noda said Tokyo would deal with the matter strictly in accordance with the law.
China said it was protesting to Japan over the detentions, China's state-run Xinhua news agency said.
"The Chinese Foreign Ministry ... is contacting the Japanese side to lodge representations over five Chinese nationals' detention on the Diaoyu Islands," Xinhua said in a brief report, referring to the isles known as Senkaku in Japan.
Friction over the uninhabited isles, near potentially rich gas deposits, had already been heating up.
"This is the most successful attempt in a decade" to reach the islands, the activist group said.
Several of the men jumped into the water, swam and waded ashore. The group said its boat had been rammed by the coastguard and hit with water cannon. A Japanese coastguard official denied that any serious damage had been done to the boat.