An opposition lawmaker and three other activists landed early May 6 on one of the Senkaku Islands, which are claimed by Japan, China and Taiwan, Maritime Safety Agency officials said.

Shingo Nishimura, a Lower House member of Shinshinto, the main opposition party, said in a statement that his group took the action "to see the state of affairs on the Senkaku Islands and the security conditions on and around the territory." Nishimura also said it was "natural for a Diet member to inspect part of Japanese territory."

Government leaders quickly expressed displeasure over his actions. It was the second time in 10 days that Japanese groups have landed on the Senkaku Islands, which lie in the East China Sea.

On April 27, Hitoshi Nakama, a member of the city assembly of Ishigaki Island, Okinawa Prefecture, and a reporter with the Sankei Shimbun newspaper briefly landed on Uotsuri Island, the largest in the Senkaku chain. Nakama also joined Nishimura when he landed on 3.8-sq.-km Uotsuri Island on May 6.

The islands are controlled by Japan but are also claimed by China and Taiwan, which call them Diaoyu and Tiaoyutai, respectively. The islands are believed to be rich in fishing resources and they sit above potentially large oil and gas reserves.

The long-standing territorial row was rekindled after a Japanese rightist group erected a beacon on one of the islands last July. At a news conference after the regular Cabinet meeting May 6, Transport Minister Makoto Koga said he confirmed that four people had landed on Uotsuri Island at around 8:30 a.m.